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Hot rolled bands and sheets are primarily low carbon steels that are produced on a Hot Strip Mill from slabs that have been thoroughly heated to a
rolling temperature of approximately 2300°F. Slab heating at this temperature accomplishes several desirable end results, which include, surface scaling
for minor surface imperfection removal, softening of the steel so it can be hot rolled, and (where applicable) dissolving carbides or nitrides that are to be
precipitated at a later stage of the rolling process. After departing the reheat furnace, the slab enters a high pressure water spray descaling unit then is
subjected to a series of 4 or 5 "roughing stands" that successively reduce the slab thickness from approximately 9-inches to 1-inch. As the slab becomes
thinner and longer by the horizontal rolls in the roughing train, the slab edges are also squeezed by vertical rolls in order to control width. Upon exiting
the last stand of the roughing train, the slab ends are sheared so a rectangular shape or "transfer bar" enters the 6 or 7 finishing stands that further reduce
the thickness of the transfer bar to the final hot rolled band or sheet gauge desired.
The last hot working operation is usually conducted above the upper critical temperature of 1450°F which permits the rolled steel to pass through a
phase transformation after all the hot work is finished. This produces a uniformly fine, equiaxed grain throughout all of the steel. If part of the hot rolling
is conducted on steel that has already partially transformed to ferrite, the deformed ferrite grains will coarsen during the self-anneal that occurs during
the cooling of the coiled steel. This condition could limit the suitability of the steel for some severe drawing applications. Attributes imparted to the
strip by the hot rolled strip mill include surface quality, thickness, width and flatness control as well as strip profile.
After leaving the last finishing stand, of the hot strip mill, the rolled strip is delivered across a runout table that is equipped with top and bottom cooling
sprays. By controlling the amount, location and flow of cooling water to which the strip is exposed, the mechanical properties and shape of the hot
rolled strip can be affected. From the runout tables, the hot rolled strip enters mandrel type coilers. Air operated pushers remove the coils from the
mandrels then place them onto a coil tilter. The coil tilter positions the coils, with their diameters upright, onto chain conveyor that transports the coils
to the coil storage area. The hot coil chain conveyor is equipped with a heavy-duty scale that accurately measures and records the weight of each coil.
1. Reheat Furnaces
Modern furnaces, with the aid of computer controls, uniformly heat continuous cast slabs to the desired temperature of approximately 2300° F.
Uniform heating provides for improved rollability, gauge control and excellent metallurgical properties.
2. Scale Breaker and Descaling Sprays
The oxide formed during reheating is removed to provide a clean surface condition for rolling in the roughing stands.
3. Roughing Stands
Reduce the slab thickness from 8" - 10" to approximately 1" for final processing in the Finishing Mills. In addition, these mills control the entry width
into the Finishing Mills and are equipped with high pressure water descaling to assure an excellent surface.
4. Crop Shear
Shears the product prior to entering the Finishing Mill to provide square head and tail ends for rolling.
5. Descaling Unit
Located immediately ahead of the Finishing Mill. This high pressure descaling unit removes any surface oxide to provide a clean surface for rolling in the
Finishing Mill.
6. Finishing Mill
Reduces the incoming 1" thick product to the final ordered thickness through successive reductions in a series of closely coupled mill stands.
7. Runout Table Cooling
Modern laminar water flow cools the strip from its Finishing Mill exit temperature to a specified coiling temperature. The cooling rate and final coiling
temperature are controlled in order to obtain the desired uniform metallurgical properties.
8. Wrap the finished strip on mandrels to provide a tight coil with uniformly straight side walls for either shipment or further
processing.
This is representative of the typical surface appearance and edge condition of Hot Rolled Sheet Non-Temper Rolled product.
HOT ROLLED COIL, HOT ROLLED SHEET
HOT ROLLED PICKLED COIL, HOT ROLLED PICKLED SHEET
Mills do not generally process sheet coils in widths narrower than 24 inch and normally consider widths less than 36 inch to be dimensionally narrow.
Mill-published price extras for narrower widths generally indicate, even in large quantities, that widths under 24" are appropriately service center
business. End users may purchase master coils directly from mills and slit them on their own equipment or have the material job [toll] slit. Any width
requiring slitting to a "multiple" width coil before re-slitting to the specified finished width is considered to be narrow. Generally speaking, slit widths
under 2" are considered to be dimensionally narrow in most thicknesses. This will vary with thickness-the heavier the thickness, the fewer are the cuts
that can be made in a single pass.
Slit coils are normally used by stampers, roll formers, and perforators who process coils to obtain optimum productivity and a minimum of waste. The
decision to use slit coil rather than flat sheet is primarily determined by the volume of material required and the availability of coil feeding equipment and
tooling designed to utilize a coil product. The alternative to slit coil is sheared-to-width, cut-length strips that require hand feeding into the die. Sheared
cut lengths are economical only when quantities are too small to justify the use of slit coil. Some manufacturing facilities still use sheared cut lengths in
quantities that would be more economically processed from coil. Conversion to coil processing is expensive, but inflation and higher labor and capital
equipment costs are making the conversion an economic necessity.
The following important requirements must be met to adequately control orders for slit coil:
1.Quantity ordered in pounds
2.Thickness of material (minimum decimal thickness is preferred)
3. Specified width of slit material in inches
4. Restricted tolerances, if any
5.Material grade
6.Acceptable coil ID sizes, either 16", 20', or 24' (preferably all three)
7.Maximum OD of coil
7.Coil spacer requirements
9.Maximum coil weight
10.Maximum skid weight
11.Method of unloading, either crane or fork Sift, from side, or rear
HSLA / SQ Denoted By: • ASTM Spec 1011 SAE J1392
CHEMISTRIES USED S - Structural Quality X - HSLA DEOXIDATTON PRACTICES 0 - Non-killed K - Killed F - Killed + Sulfide Shape Control
The hot rolled band product produced by the hot strip (sheet) mill is coiled with a 30" ID and has a mill edge. Bands may be shipped as-is or edge-
trimmed into a hot rolled sheet product. Hot-rolled cut edge sheet may be sold as 24" ID coil or as leveled and cut-to-length flat sheet for shipment in
either a hot rolled "black" (unpickled) dry surface or in a pickled and oiled surface. Most Hot Rolled Commercial Steel sheet to ASTM A1011 (old
ASTM A569). This specification will usually provide steel with a chemical analysis of .15% max. carbon, .60% max. manganese, .030% max.
phosphorus, and .035% max. sulfur and a bend test to assure that the sheet is capable of withstanding a 180 degree flat bend on itself in any direction.
During fabrication, the minimum inside bend radius should be equal to one material thickness (It) whenever possible to eliminate or minimize cracks in
forming. It is always good fabricating practice to remove shear burr from the edges of the sheet. If this is not practical, position the material such that the
burr will be on the inside of the bend. Variations in hardness will result within a given shipment because of the normal chemical segregation in the
material and the fact that HR sheet is not annealed during production. Typically, one may expect hardness values of approximately Rockwell-B 50-75,
but no guarantee can be made. Hot Rolled Commercial Steel (CS) is the least expensive steel sheet grade produced and exhibits a tight blue-black oxide
scale on its surface. Material is ordered dry (not oiled) and is normally used in applications where surface appearance is not important. It is not suitable
for painting where long-term paint adhesion is required. The oxide scale can flake off in fabrication and will carry the paint with it. The typical
mechanical properties for HR CS sheet are to be interpreted as typical only; they are not intended to be used as specification limits.
Typical Mechanical Properties
Designation Yield Strength KS1 % El (2") Min
CS Type A, B & C 30/50 25
FS TypeA&B 30/45 28
DS TypeA&B 30/45 28
HOT ROLLED PRODUCT DESCRIPTIONS
Commercial Steel Type A C .lO% max. Mn .60% max.
Commercial Steel Type B C .02 /.15% Mn .60% max.
Commercial Steel Type C C .08% max. Mn .60% max. P .100% max.
Commercial Steel Type D C .10% max. Mn .70% max.
Drawing Steel Type A C .08% max. Mn .50% max. Stabilized at producers option
Drawing Steel Type B C .02 / .08% Mn .50% max.
Structural Steel SS Produced to specified mechanic properties
Structural Steel HSLA Produced to specified mechanic properties
PICKLED AND OILED
Hot rolled pickled and oiled coil and cut-length flat sheet have the same characteristics as HR CS dry "black" sheet except that the surface is scale-free
and oiled. The continuous hydrochloric acid pickling process is used by all major mill producers, yielding a sheet with a uniform, scale-free surface (see
below). This pickling process chemically removes the hot rolled scale from the surface. The material is then normally oiled to prevent rusting, using a
corrosion-preventative oil that is easily removed by conventional degreasing methods. After degreasing and proper surface preparation, HR pickled
sheet can be painted, permitting a good bond of paint to steel, since the problem of flaking of the oxide scale is eliminated. The finish of hot rolled
pickled and oiled sheet is best described as a heavy matte finish. In general, the surface appearance is quite good; however, the scale-free surface will
exhibit minor surface imperfections that would not normally be apparent if the original mill scale were present. This product is typically used for
industrial electrical cabinets, lawn and agricultural implements, truck parts, trailers, and similar structural applications that require relatively durable
paint adhesion. Heavier dull paint tends to cover these surface imperfections better than high gloss paint. Occasionally, customers will specify pickled
dry sheets because they are not equipped to remove the oil. A pickled dry surface will rust quickly and is entirely the responsibility of the customer.
Product processed through the pickle line is designated as Hot Rolled Sheet Pickled or Hot Rolled Sheet Pickled Non-Temper Rolled. Product
designated as Hot Rolled Sheet Pickled is processed through the pickle line and temper rolled. Alternately, product designated as Hot Rolled Sheet
Pickled Non-Temper Rolled is processed only through the pickle line with no additional processing. Therefore, any pickled applications requiring
guaranteed flatness must be ordered Hot Rolled Sheet Pickled. In either case, the pickling operation results in coils that have a clean bright grayish
surface. The coil ends are cropped back to gauge. These products may be ordered as dry, oiled, mill edge or side trimmed edge. When ordered as side
trimmed edge, the product will exhibit a uniform edge with excellent width control. These edges result in better conditions for welding as compared to a
mill edge. When product is ordered as oiled, a film of oil will be applied for rust and surface protection. Special precautions to prevent rust must be
taken on any product ordered dry.
1. Uncoiler
Receives coils from the hot strip mill and unwraps them for processing through the pickle line.
2. Processor
Primary purpose is to minimize tendency for coil breaks by alternately flexing the steel around a series of small diameter rolls. In addition, the surface
oxide is cracked for improved pickling
3. Shear and Welder
Provide square coil ends which are welded together, so strip can be processed continuously through the pickle line.
4. Temper Mill
Primary purpose is to increase pickling efficiency by breaking the surface oxide which forms on the strip surface at the exit end of the Hot Strip Mill. In
addition, the temper mill provides some degree of improved strip flatness.
5. Pickle Tanks
Remove the surface oxide from the strip by a chemical reaction with Hydrochloric Acid (HCL). This results in a bright, oxide-free surface that is
required for many customer hot rolled product applications or for further processing into cold rolled or coated sheet products.
6. Rinse Tanks
Cascading water rinses clean any residual acid from the strip surface.
7. Dryer
Removes any excess water to prevent surface rust or stain.
8. Shear
Cuts coils to the desired weight for shipment or processing.
9. Oiler
Provides a film of oil for rust protection as well as protection against wrap to wrap gouging during handling and further processing.
10. Side Trimmer
Cuts each edge of the strip to provide uniform edges with excellent width control.
11. Recoiler
Wraps the pickled strip into a tight coil with straight side walls for shipment or further processing.
This is representative of a typical surface appearance along with a side trimmed edge of Hot Rolled Sheet Pickled product.
Temper Mill
All products ordered as Hot Rolled Sheet or Hot Rolled Sheet Pickled receive a temper rolling operation.
The temper rolling process is performed to improve the sheet flatness, to remove yield point elongation and to impart a uniform surface on the sheet.
For these reasons, applications requiring good flatness or surface must be temper rolled.
1. Uncoiler
Receives coils from the hot strip mill or pickle line and unwraps coil for processing through the temper mill.
2. Temper Mill
Rolls the strip with controlled extensions to improve flatness, remove yield point elongation and provide a uniform surface.
3. Recoiler
Wraps the temper rolled strip into a tight coil with straight side walls for shipment.
HIGH STRENGTH LOW ALLOY STEEL SHEET
GENERAL INFORMATION
High Strength Low Alloy (HSLA) steels, sometimes referred to as microalloyed, are a growing family of steels designed or "tailored" to achieve higher
strength properties combined with ductility, formability, weldability, atmospheric corrosion resistance, toughness, and fatigue strength. One of the
earliest HSLA grades is Cor-Ten. Introduced by U.S. Steel Corporation in 1933, it was engineered for increased strength and atmospheric corrosion
resistance. Most major steel companies have developed and produced an expanded complex of HSLA grades that have been added to this category. With
the increasing variety of HSLA grades, ASTM has established a series of general HSLA categories, most with specific sub-grades requiring minimum
physical and chemical properties. HSLA steels achieve their optimum combination of properties from the balanced additions of small amounts of
alloying elements that include vanadium, columbium, nitrogen, phosphorus, and copper. These steels are normally in the as-rolled condition and are
manufactured to minimum mechanical properties. In the majority of cases, no heat treating is performed on the hot rolled sizes. Sheet thicknesses lighter
than 14 gage are normally produced as a cold rolled product. In order to restore ductility, some grades of cold rolled HSLA material are annealed and
therefore will have slightly lower guaranteed minimum mechanical properties. The most popular HSLA grades are produced to 5O.OOO psi minimum
yield strength, which represents a 60% increase in yield strength over HR or CR mild steel. Other grades (Cor-Ten) have special atmospheric corrosion
resistance characteristics, which permit savings in maintenance costs. Copper, when added to steel in amounts up to 0.50%, will provide enhanced
atmospheric corrosion resistance along with improved paint adhesion when applications call for full weather exposure. Copper-bearing steels (O.20%
copper minimum) are sometimes specified by customers when the finished part is subject to atmospheric corrosion. Essentially, any low carbon steel
can be produced as a copper-bearing grade if so specified. Higher strength steels permit redesigning using lighter sections, resulting in lower costs for
material and shipping. Maintaining the same thickness as that off mild steel will result in a stronger, more durable product with no increase in weight.
HSLA steels can be worked in press brakes and other forming equipment. In actual I fabrication, their higher strength requires greater force and more
liberal bend radii as compared to low carbon steel. Bending should be performed more slowly with proper attention to edges (burr removed, corners
slightly rounded). Whenever possible, bending should be with the axis of the bend transverse to the original rolling direction. Forming should be avoided
when the steel is extremely cold. Bending material below room temperature is not recommended. Punching will require 20% to 40% more power as
compared to equal thicknesses of low carbon steel. Conventional gas cutting techniques used on low carbon steel are applicable to HSLA steels.
Typical end uses of HSLA steels include: Railroad cars, Agricultural equipment, Trucks, Auto mobile components, Trailers, Crane booms, Cargo
containers, Television towers, Mobile machinery, Building structures, Under frames, Transmission towers, and Water heater tanks.
AISI NOMENCLATURE
The American Iron & Steel Institute (AISI) has developed a simplified designation system for high strength sheet to eliminate the difficulties
encountered when similar products with varying trade names are compared. This new AISI designation system has three basic components:
1. The minimum yield strength in ksi using three digits. (1 ,OOO psi equal 1) Example: 50 ksi minimum yield strength is designated as 050.
2. A chemical composition classification using one letter: S = Structural Quality X = Low Alloy (HSLA) W = Weathering (Cor-Ten Types)
3. A classification for the deoxidation practice using one letter: O = Non-Killed K = Killed F = Killed plus inclusion control
This AISI designation system results in a five character designator.
Example: Ex-Ten H50/INX-50 = 050XO (50 ksi yield; low alloy; non-killed) Cor-Ten A = 050WK (50 ksi yield; weathering; killed)
This general description of the new AISI nomenclature system is complete for the high strength material that we presently stock. If you encounter
variations of this system that are not explained using the above letter designations, please contact Kieh Co. for further information.
DRAWING STEELS
2 DISTINCT TYPES
Drawing Steel Type A C .08% max. Mn .50% max. Vacuum degassed at producers option
Drawing Steel Type B C .02 / .08% Mn .50% max.
rolling temperature of approximately 2300°F. Slab heating at this temperature accomplishes several desirable end results, which include, surface scaling
for minor surface imperfection removal, softening of the steel so it can be hot rolled, and (where applicable) dissolving carbides or nitrides that are to be
precipitated at a later stage of the rolling process. After departing the reheat furnace, the slab enters a high pressure water spray descaling unit then is
subjected to a series of 4 or 5 "roughing stands" that successively reduce the slab thickness from approximately 9-inches to 1-inch. As the slab becomes
thinner and longer by the horizontal rolls in the roughing train, the slab edges are also squeezed by vertical rolls in order to control width. Upon exiting
the last stand of the roughing train, the slab ends are sheared so a rectangular shape or "transfer bar" enters the 6 or 7 finishing stands that further reduce
the thickness of the transfer bar to the final hot rolled band or sheet gauge desired.
The last hot working operation is usually conducted above the upper critical temperature of 1450°F which permits the rolled steel to pass through a
phase transformation after all the hot work is finished. This produces a uniformly fine, equiaxed grain throughout all of the steel. If part of the hot rolling
is conducted on steel that has already partially transformed to ferrite, the deformed ferrite grains will coarsen during the self-anneal that occurs during
the cooling of the coiled steel. This condition could limit the suitability of the steel for some severe drawing applications. Attributes imparted to the
strip by the hot rolled strip mill include surface quality, thickness, width and flatness control as well as strip profile.
After leaving the last finishing stand, of the hot strip mill, the rolled strip is delivered across a runout table that is equipped with top and bottom cooling
sprays. By controlling the amount, location and flow of cooling water to which the strip is exposed, the mechanical properties and shape of the hot
rolled strip can be affected. From the runout tables, the hot rolled strip enters mandrel type coilers. Air operated pushers remove the coils from the
mandrels then place them onto a coil tilter. The coil tilter positions the coils, with their diameters upright, onto chain conveyor that transports the coils
to the coil storage area. The hot coil chain conveyor is equipped with a heavy-duty scale that accurately measures and records the weight of each coil.
1. Reheat Furnaces
Modern furnaces, with the aid of computer controls, uniformly heat continuous cast slabs to the desired temperature of approximately 2300° F.
Uniform heating provides for improved rollability, gauge control and excellent metallurgical properties.
2. Scale Breaker and Descaling Sprays
The oxide formed during reheating is removed to provide a clean surface condition for rolling in the roughing stands.
3. Roughing Stands
Reduce the slab thickness from 8" - 10" to approximately 1" for final processing in the Finishing Mills. In addition, these mills control the entry width
into the Finishing Mills and are equipped with high pressure water descaling to assure an excellent surface.
4. Crop Shear
Shears the product prior to entering the Finishing Mill to provide square head and tail ends for rolling.
5. Descaling Unit
Located immediately ahead of the Finishing Mill. This high pressure descaling unit removes any surface oxide to provide a clean surface for rolling in the
Finishing Mill.
6. Finishing Mill
Reduces the incoming 1" thick product to the final ordered thickness through successive reductions in a series of closely coupled mill stands.
7. Runout Table Cooling
Modern laminar water flow cools the strip from its Finishing Mill exit temperature to a specified coiling temperature. The cooling rate and final coiling
temperature are controlled in order to obtain the desired uniform metallurgical properties.
8. Wrap the finished strip on mandrels to provide a tight coil with uniformly straight side walls for either shipment or further
processing.
This is representative of the typical surface appearance and edge condition of Hot Rolled Sheet Non-Temper Rolled product.
HOT ROLLED COIL, HOT ROLLED SHEET
HOT ROLLED PICKLED COIL, HOT ROLLED PICKLED SHEET
Mills do not generally process sheet coils in widths narrower than 24 inch and normally consider widths less than 36 inch to be dimensionally narrow.
Mill-published price extras for narrower widths generally indicate, even in large quantities, that widths under 24" are appropriately service center
business. End users may purchase master coils directly from mills and slit them on their own equipment or have the material job [toll] slit. Any width
requiring slitting to a "multiple" width coil before re-slitting to the specified finished width is considered to be narrow. Generally speaking, slit widths
under 2" are considered to be dimensionally narrow in most thicknesses. This will vary with thickness-the heavier the thickness, the fewer are the cuts
that can be made in a single pass.
Slit coils are normally used by stampers, roll formers, and perforators who process coils to obtain optimum productivity and a minimum of waste. The
decision to use slit coil rather than flat sheet is primarily determined by the volume of material required and the availability of coil feeding equipment and
tooling designed to utilize a coil product. The alternative to slit coil is sheared-to-width, cut-length strips that require hand feeding into the die. Sheared
cut lengths are economical only when quantities are too small to justify the use of slit coil. Some manufacturing facilities still use sheared cut lengths in
quantities that would be more economically processed from coil. Conversion to coil processing is expensive, but inflation and higher labor and capital
equipment costs are making the conversion an economic necessity.
The following important requirements must be met to adequately control orders for slit coil:
1.Quantity ordered in pounds
2.Thickness of material (minimum decimal thickness is preferred)
3. Specified width of slit material in inches
4. Restricted tolerances, if any
5.Material grade
6.Acceptable coil ID sizes, either 16", 20', or 24' (preferably all three)
7.Maximum OD of coil
7.Coil spacer requirements
9.Maximum coil weight
10.Maximum skid weight
11.Method of unloading, either crane or fork Sift, from side, or rear
HSLA / SQ Denoted By: • ASTM Spec 1011 SAE J1392
CHEMISTRIES USED S - Structural Quality X - HSLA DEOXIDATTON PRACTICES 0 - Non-killed K - Killed F - Killed + Sulfide Shape Control
The hot rolled band product produced by the hot strip (sheet) mill is coiled with a 30" ID and has a mill edge. Bands may be shipped as-is or edge-
trimmed into a hot rolled sheet product. Hot-rolled cut edge sheet may be sold as 24" ID coil or as leveled and cut-to-length flat sheet for shipment in
either a hot rolled "black" (unpickled) dry surface or in a pickled and oiled surface. Most Hot Rolled Commercial Steel sheet to ASTM A1011 (old
ASTM A569). This specification will usually provide steel with a chemical analysis of .15% max. carbon, .60% max. manganese, .030% max.
phosphorus, and .035% max. sulfur and a bend test to assure that the sheet is capable of withstanding a 180 degree flat bend on itself in any direction.
During fabrication, the minimum inside bend radius should be equal to one material thickness (It) whenever possible to eliminate or minimize cracks in
forming. It is always good fabricating practice to remove shear burr from the edges of the sheet. If this is not practical, position the material such that the
burr will be on the inside of the bend. Variations in hardness will result within a given shipment because of the normal chemical segregation in the
material and the fact that HR sheet is not annealed during production. Typically, one may expect hardness values of approximately Rockwell-B 50-75,
but no guarantee can be made. Hot Rolled Commercial Steel (CS) is the least expensive steel sheet grade produced and exhibits a tight blue-black oxide
scale on its surface. Material is ordered dry (not oiled) and is normally used in applications where surface appearance is not important. It is not suitable
for painting where long-term paint adhesion is required. The oxide scale can flake off in fabrication and will carry the paint with it. The typical
mechanical properties for HR CS sheet are to be interpreted as typical only; they are not intended to be used as specification limits.
Typical Mechanical Properties
Designation Yield Strength KS1 % El (2") Min
CS Type A, B & C 30/50 25
FS TypeA&B 30/45 28
DS TypeA&B 30/45 28
HOT ROLLED PRODUCT DESCRIPTIONS
Commercial Steel Type A C .lO% max. Mn .60% max.
Commercial Steel Type B C .02 /.15% Mn .60% max.
Commercial Steel Type C C .08% max. Mn .60% max. P .100% max.
Commercial Steel Type D C .10% max. Mn .70% max.
Drawing Steel Type A C .08% max. Mn .50% max. Stabilized at producers option
Drawing Steel Type B C .02 / .08% Mn .50% max.
Structural Steel SS Produced to specified mechanic properties
Structural Steel HSLA Produced to specified mechanic properties
PICKLED AND OILED
Hot rolled pickled and oiled coil and cut-length flat sheet have the same characteristics as HR CS dry "black" sheet except that the surface is scale-free
and oiled. The continuous hydrochloric acid pickling process is used by all major mill producers, yielding a sheet with a uniform, scale-free surface (see
below). This pickling process chemically removes the hot rolled scale from the surface. The material is then normally oiled to prevent rusting, using a
corrosion-preventative oil that is easily removed by conventional degreasing methods. After degreasing and proper surface preparation, HR pickled
sheet can be painted, permitting a good bond of paint to steel, since the problem of flaking of the oxide scale is eliminated. The finish of hot rolled
pickled and oiled sheet is best described as a heavy matte finish. In general, the surface appearance is quite good; however, the scale-free surface will
exhibit minor surface imperfections that would not normally be apparent if the original mill scale were present. This product is typically used for
industrial electrical cabinets, lawn and agricultural implements, truck parts, trailers, and similar structural applications that require relatively durable
paint adhesion. Heavier dull paint tends to cover these surface imperfections better than high gloss paint. Occasionally, customers will specify pickled
dry sheets because they are not equipped to remove the oil. A pickled dry surface will rust quickly and is entirely the responsibility of the customer.
Product processed through the pickle line is designated as Hot Rolled Sheet Pickled or Hot Rolled Sheet Pickled Non-Temper Rolled. Product
designated as Hot Rolled Sheet Pickled is processed through the pickle line and temper rolled. Alternately, product designated as Hot Rolled Sheet
Pickled Non-Temper Rolled is processed only through the pickle line with no additional processing. Therefore, any pickled applications requiring
guaranteed flatness must be ordered Hot Rolled Sheet Pickled. In either case, the pickling operation results in coils that have a clean bright grayish
surface. The coil ends are cropped back to gauge. These products may be ordered as dry, oiled, mill edge or side trimmed edge. When ordered as side
trimmed edge, the product will exhibit a uniform edge with excellent width control. These edges result in better conditions for welding as compared to a
mill edge. When product is ordered as oiled, a film of oil will be applied for rust and surface protection. Special precautions to prevent rust must be
taken on any product ordered dry.
1. Uncoiler
Receives coils from the hot strip mill and unwraps them for processing through the pickle line.
2. Processor
Primary purpose is to minimize tendency for coil breaks by alternately flexing the steel around a series of small diameter rolls. In addition, the surface
oxide is cracked for improved pickling
3. Shear and Welder
Provide square coil ends which are welded together, so strip can be processed continuously through the pickle line.
4. Temper Mill
Primary purpose is to increase pickling efficiency by breaking the surface oxide which forms on the strip surface at the exit end of the Hot Strip Mill. In
addition, the temper mill provides some degree of improved strip flatness.
5. Pickle Tanks
Remove the surface oxide from the strip by a chemical reaction with Hydrochloric Acid (HCL). This results in a bright, oxide-free surface that is
required for many customer hot rolled product applications or for further processing into cold rolled or coated sheet products.
6. Rinse Tanks
Cascading water rinses clean any residual acid from the strip surface.
7. Dryer
Removes any excess water to prevent surface rust or stain.
8. Shear
Cuts coils to the desired weight for shipment or processing.
9. Oiler
Provides a film of oil for rust protection as well as protection against wrap to wrap gouging during handling and further processing.
10. Side Trimmer
Cuts each edge of the strip to provide uniform edges with excellent width control.
11. Recoiler
Wraps the pickled strip into a tight coil with straight side walls for shipment or further processing.
This is representative of a typical surface appearance along with a side trimmed edge of Hot Rolled Sheet Pickled product.
Temper Mill
All products ordered as Hot Rolled Sheet or Hot Rolled Sheet Pickled receive a temper rolling operation.
The temper rolling process is performed to improve the sheet flatness, to remove yield point elongation and to impart a uniform surface on the sheet.
For these reasons, applications requiring good flatness or surface must be temper rolled.
1. Uncoiler
Receives coils from the hot strip mill or pickle line and unwraps coil for processing through the temper mill.
2. Temper Mill
Rolls the strip with controlled extensions to improve flatness, remove yield point elongation and provide a uniform surface.
3. Recoiler
Wraps the temper rolled strip into a tight coil with straight side walls for shipment.
HIGH STRENGTH LOW ALLOY STEEL SHEET
GENERAL INFORMATION
High Strength Low Alloy (HSLA) steels, sometimes referred to as microalloyed, are a growing family of steels designed or "tailored" to achieve higher
strength properties combined with ductility, formability, weldability, atmospheric corrosion resistance, toughness, and fatigue strength. One of the
earliest HSLA grades is Cor-Ten. Introduced by U.S. Steel Corporation in 1933, it was engineered for increased strength and atmospheric corrosion
resistance. Most major steel companies have developed and produced an expanded complex of HSLA grades that have been added to this category. With
the increasing variety of HSLA grades, ASTM has established a series of general HSLA categories, most with specific sub-grades requiring minimum
physical and chemical properties. HSLA steels achieve their optimum combination of properties from the balanced additions of small amounts of
alloying elements that include vanadium, columbium, nitrogen, phosphorus, and copper. These steels are normally in the as-rolled condition and are
manufactured to minimum mechanical properties. In the majority of cases, no heat treating is performed on the hot rolled sizes. Sheet thicknesses lighter
than 14 gage are normally produced as a cold rolled product. In order to restore ductility, some grades of cold rolled HSLA material are annealed and
therefore will have slightly lower guaranteed minimum mechanical properties. The most popular HSLA grades are produced to 5O.OOO psi minimum
yield strength, which represents a 60% increase in yield strength over HR or CR mild steel. Other grades (Cor-Ten) have special atmospheric corrosion
resistance characteristics, which permit savings in maintenance costs. Copper, when added to steel in amounts up to 0.50%, will provide enhanced
atmospheric corrosion resistance along with improved paint adhesion when applications call for full weather exposure. Copper-bearing steels (O.20%
copper minimum) are sometimes specified by customers when the finished part is subject to atmospheric corrosion. Essentially, any low carbon steel
can be produced as a copper-bearing grade if so specified. Higher strength steels permit redesigning using lighter sections, resulting in lower costs for
material and shipping. Maintaining the same thickness as that off mild steel will result in a stronger, more durable product with no increase in weight.
HSLA steels can be worked in press brakes and other forming equipment. In actual I fabrication, their higher strength requires greater force and more
liberal bend radii as compared to low carbon steel. Bending should be performed more slowly with proper attention to edges (burr removed, corners
slightly rounded). Whenever possible, bending should be with the axis of the bend transverse to the original rolling direction. Forming should be avoided
when the steel is extremely cold. Bending material below room temperature is not recommended. Punching will require 20% to 40% more power as
compared to equal thicknesses of low carbon steel. Conventional gas cutting techniques used on low carbon steel are applicable to HSLA steels.
Typical end uses of HSLA steels include: Railroad cars, Agricultural equipment, Trucks, Auto mobile components, Trailers, Crane booms, Cargo
containers, Television towers, Mobile machinery, Building structures, Under frames, Transmission towers, and Water heater tanks.
AISI NOMENCLATURE
The American Iron & Steel Institute (AISI) has developed a simplified designation system for high strength sheet to eliminate the difficulties
encountered when similar products with varying trade names are compared. This new AISI designation system has three basic components:
1. The minimum yield strength in ksi using three digits. (1 ,OOO psi equal 1) Example: 50 ksi minimum yield strength is designated as 050.
2. A chemical composition classification using one letter: S = Structural Quality X = Low Alloy (HSLA) W = Weathering (Cor-Ten Types)
3. A classification for the deoxidation practice using one letter: O = Non-Killed K = Killed F = Killed plus inclusion control
This AISI designation system results in a five character designator.
Example: Ex-Ten H50/INX-50 = 050XO (50 ksi yield; low alloy; non-killed) Cor-Ten A = 050WK (50 ksi yield; weathering; killed)
This general description of the new AISI nomenclature system is complete for the high strength material that we presently stock. If you encounter
variations of this system that are not explained using the above letter designations, please contact Kieh Co. for further information.
DRAWING STEELS
2 DISTINCT TYPES
Drawing Steel Type A C .08% max. Mn .50% max. Vacuum degassed at producers option
Drawing Steel Type B C .02 / .08% Mn .50% max.
MM 005 : Hot Rolled
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