Automotive Worldwide
High strength low alloy (HSLA) steels for cold forming
Extract from the product catalogue -European edition
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We are also reachable by the e-mail address [email protected].
High strength low alloy (HSLA) steels for cold forming High yield and tensile strengthsteels
Description
Steels in the HSLA (High Strength Low Alloy) range are hardened by a combination of precipitation and grain size refining, resulting in high strength with low alloy content. This enhances weldability and choice of coatings, since these steels exhibit neither weld zone softening nor grain coarsening. These grades are particularly suitable for structural components such as suspension systems and chassis and reinforcement parts.For their respective yield strength levels, these steels all exhibit excellent cold forming and low-temperature brittle fracture strength (starting at grade 320).The entire range of HSLA steels offers good fatigue strength (suspension arm, shock tower) and impact strength (longitudinal beams, cross members, reinforcements, etc.).Because of their mechanical strength, the weight of reinforcement and structural components can be reduced.The HSLA range of products is available in hot and cold rolled grades. The various grades are identified by their yield strength.Hot rolled HSLA grades can be given a Class 1 hot-dip galvanized coating according to the EN 36503 standard (post-galvanizing).
Applications
The steels in the HSLA range are suitable for structural parts such as suspension systems, reinforcements, cross members, longitudinal beams, chassis components, etc. The mechanical properties of hot rolled HSLA steels and their excellent cold forming performance and low-temperature brittle fracture resistance support cost-effective solutions for many parts and sub-assemblies for which weight, thickness and size reduction are sought, such as:
chassis components;wheels;slide rails;cross members.
Rear cross member in Extragal®-coated HSLA 300
Front reinforcement in Dual Phase 780Shock absorber in HSLA 300
Designation and standard
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Designation and standard
Euronorms VDA 239-100
HSLA 260HC260LA (+ZE) /HX260LAD (+Z,
+ZF, +ZA) CR240LA (-UNC,-EG,-GI,-GA)
HSLA 300HC300LA (+ZE) /HX300LAD (+Z,
+ZF, +ZA) CR270LA (-UNC,-EG,-GI,-GA)
HSLA 340HC340LA (+ZE) /HX340LAD (+Z,
+ZF, +ZA) CR300LA (-UNC,-EG,-GI,-GA)
HSLA 380HC380LA (+ZE) /HX380LAD (+Z,
+ZF, +ZA) CR340LA (-UNC,-EG,-GI,-GA)
HSLA 420HC420LA (+ZE) /HX420LAD (+Z,
+ZF, +ZA) CR420LA (-UNC,-EG,-GI,-GA)
Euronorms Uncoated ( EN 10268: 2006+A1: 2013): Steel grade nameElectrogalvanized (EN 10268 :2006+A1: 2013 + EN 10152 :2017): Steel grade name +ZEGalvannealed (EN 10346 :2015): Steel grade name +ZFExtragal® (EN 10346 :2015): Steel grade name +ZGalfan (EN 10346 :2015): Steel grade name +ZA
VDA 239-100 Uncoated: Steel grade name-UNCElectrogalvanized: Steel grade name-EGGalvannealed: Steel grade name-GAExtragal®: Steel grade name-GI
Hot rolled Cold rolled
While the ArcelorMittal grades conform perfectly well to the indicated EN standards, ArcelorMittal grades generally offer tighter mechanical properties (see table below).
Euronorms VDA 239-100
HSLA 320 S315MC/HX340LAD (+Z) HR300LA (-UNC,-GI) HSLA 360 S355MC/HX380LAD (+Z) HR340LA (UNC,-GI) HSLA 420 S420MC/HX420LAD (+Z) HR420LA (-UNC,-GI) HSLA 460 S460MC/HX460LAD (+Z) HR460LA (-UNC,-GI) HSLA 500 S500MC/HX500LAD (+Z) HR500LA (-UNC,-GI) HSLA 550 S550MC HR550LA (-UNC,-GI)
Euronorms Uncoated (EN 10149-2 :1995): Steel grade name
VDA 239-100 Uncoated: Steel grade name-UNCExtragal®: Steel grade name-GI
Hot rolled Cold rolled
While the ArcelorMittal grades conform perfectly well to the indicated EN standards, ArcelorMittal grades generally offer tighter mechanical properties (see table below).The above indicative tables summarize the European and VDA standards corresponding to the ArcelorMittal product range.
Technical characteristics
Mechanical propertiesGuaranteed for uncoated sheet in the transverse direction.
YS (MPa) UTS (MPa)ef (%)
L0 = 80 mmth < 3 mm
HSLA 260 260 -320 350 -410 ≥ 28 HSLA 300 300 -360 390 -450 ≥ 26 HSLA 340 340 -400 420 -490 ≥ 23 HSLA 380 380 -450 460 -530 ≥ 20 HSLA 420 420 -520 470 -590 ≥ 17
Hot rolled Cold rolled
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Guaranteed for uncoated sheet in the rolling direction.
YS (MPa) UTS (MPa)ef (%)
L0 = 80 mmth < 3 mm
Ef (%)L0 = 5,65 √S0 (mm)
th ≥ 3 mm
HSLA 320 325 -385 415 -470 ≥ 24 ≥ 28 HSLA 360 360 -435 450 -520 ≥ 21 ≥ 25 HSLA 420 420 -500 490 -570 ≥ 20 ≥ 23 HSLA 460 460 -550 550 -650 ≥ 17 ≥ 21 HSLA 500 500 -590 570 -670 ≥ 15 ≥ 19 HSLA 550 550 -650 650 -730 ≥ 15 ≥ 18
Hot rolled Cold rolled
Because HSLA steels can exhibit an extended elastic-plastic transition zone with variations in YS values, by convention only the lower yield strength (LYS) is taken into account in this zone.
Microstructure of a cold rolled HSLA 340 steel
Chemical composition (%)
C Mn Si Max Max Max
HSLA 260 0,080 0,50 0,04 HSLA 300 0,080 0,60 0,04 HSLA 340 0,080 0,70 0,04 HSLA 380 0,080 0,90 0,35 HSLA 420 0,140 1,60 0,40 HSLA 320 0,080 0,50 0,03 HSLA 360 0,080 0,60 0,03 HSLA 420 0,080 0,75 0,03 HSLA 460 0,120 1,60 0,40 HSLA 500 0,090 1,50 0,03 HSLA 550 0,090 1,65 0,35
Hot rolled Cold rolled
Available coatings and Worldwide availability
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Available coatings and Worldwide availability
Uncoated Electrogalvanized
EUR NAM SAM RSA CHI EUR NAM SAM RSA CHI
HSLA 260
HSLA 300
HSLA 340
HSLA 380
HSLA 420
HSLA 320
HSLA 360
HSLA 420
HSLA 460
HSLA 500
HSLA 550
Extragal® Galvannealed
EUR NAM SAM RSA CHI EUR NAM SAM RSA CHI
HSLA 260
HSLA 300
HSLA 340
HSLA 380
HSLA 420
HSLA 320
HSLA 360
HSLA 420
HSLA 460
HSLA 500
HSLA 550
Hot rolled Cold rolled
Available in non-visible part quality Undergoing customer testing Under development Available in visible and non-visible part quality (Z)
EUR : Europe Region -NAM : North America Region -SAM : South America Region -RSA : South Africa Region -CHI : China
X Available
Please consult us about the availability of additional HSLA products.
Recommendations for use and secondary processing
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FormingDrawability declines progressively with increasing yield strength. Forming limit curves can be used to define maximum strains without necking for different deformation paths.
Example of forming limit curves calculated for cold rolled HSLA sheet (thickness: 1.0 mm)
We can provide additional forming data for steels in the HSLA range with particular thicknesses and coatings.
Welding
Weldability is determined according to the ISO 18278-2 method.
Welding range (kA)
HSLA 300 Extragal®
(thickness: 2 mm) 3,5
HSLA 340 Extragal®
(thickness: 1 mm) 1,1
Hot rolled Cold rolled
Cold rolledHSLA steels can be readily welded using all common welding processes.
Based on long experience in the characterization of its products, ArcelorMittal can provide technical assistance in adjusting the resistance spot and arc welding parameters of any steel in the HSLA range.
Fatigue strength
HSLA steels have good fatigue strength.
Examples of Wöhler curves for a variety of HSLA steels are given in the graph below. The curves plot maximum stress versus number of cycles to failure. They are calculated for a tension-tension loading ratio of R = 0.1.
Wöhler curves for cold rolled HSLA steels
Because of their high endurance limits, these steels are particularly well suited to parts subject to fatigue stress. To restore the base metal endurance limit adjacent to welds in areas subjected to severe cyclic loading, a post-weld treatment such as TIG melting, hammering, peening or grinding should be applied to the weld toe.
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Because of their high endurance limits, these steels are particularly well suited to parts subject to fatigue stress. To restore the base metal endurance limit adjacent to welds in areas subjected to severe cyclic loading, a post-weld treatment such as TIG melting, hammering, peening or grinding should be applied to the weld toe.Hot rolled grades above HSLA 420 in thicknesses greater than 6 mm are generally used for fatigue applications and applications involving straightening and stress relieving treatments. These steels cannot be heated above 700°C without risk of impairing the mechanical properties obtained by thermo-mechanical treatment.
ArcelorMittal can make available a comprehensive database concerning the fatigue performance of the steels in its HSLA range.
© ArcelorMittal | Last update: 03-05-2018
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