Product Range

Available Dimensions for Grades

Commercial

Drawing

IF

IFHS

C-Mn

Re-Phosphorized

DP (<700MPa)

DP (UTS>800 MPa)

HSLA

Bake Hardening

Advanced High Strength Steel

Dual Phase steels DP600 and DP780 offer an excellent combination of strength and drawability as a result of their microstructure, in which a hard martensitic or bainitic phase is dispersed in a soft ferritic matrix.

These steels have high strain hardenability which provide them good strain redistribution capacity and thus drawability as well as finished part mechanical properties, including yield strength, that are far superior to those of the initial blank.

The yield strength of Dual Phase steels is further increased by the paint baking (also called Bake Hardening, BH) process. High finished part mechanical strength lends these steels excellent fatigue strength and good energy absorption capacity, making them suitable for use in structural parts and reinforcements.

The strain hardening capacity of these steels combined with a strong bake hardening effect gives them excellent potential for reducing the weight of structural parts.

Service Properties of Dual Phase Steel

*The service properties of Dual Phase steels are guaranteed by the controlled (temperature, cooling rate) annealing cycle in particular ensures achievment of the Dual Phase microstructure and reproducibility of mechanical properties.

Designation and Standard

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prEN 10338:2009 prJFS A2001_2008 prJIS G_3135_2006
Dual Phase 590 HCT600X JSC590Y SPFC590Y
Dual Phase 780 HCT780X JSC780Y SPFC780Y
Dual Phase 980 HCT980X JSC980Y SPFC980Y

Mechanical Properties prJFS A2001_2008

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Grade YS (N/mm2) UTS (N/mm2) El %
JSC590Y 320-440 >590 ≥19
JSC780Y 420-590 >780 ≥14
JSC980Y 580-730 >980 ≥11

Notes

  • 1N/mm2 = 1MPa
  • Yield strength refers to the 0.2% proof strength for the product
  • JSW DP steel comfortably meets the ‘n’ value, BH and Hole Expansibility requirements
  • JSW DP steels confirms Ageing Guarantee of 6 Months

Applications

Given their high energy absorption capacity and fatigue strength, cold rolled Dual Phase Steels are particularly well suited for automotive structural and safety parts such as longitudinal beams, cross members and reinforcements.

Typical Mechanical Properties of DP Grades at JSW Steel

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Grade YS (N/mm2) UTS (N/mm2) El % n-value BH Index
(MPa)
Hole
Expansion Ratio
JSC590Y 380-400 610-640 27-30 0.16 50-60 60%
JSC780Y 540-570 800-830 19-22 - >35 40%
JSC980Y 660-700 1020-1050 13-15 - >35 30%

*JSW DP Steel comfortably fulfill the aging guarantee of more than 6 months

Phosphatability Test - DP600

Phosphatability Test - DP600

*JSW DP Steel comfortably satisfy the posibility test requirements having very fine and even phosphate crystal size with Phosphatability ratio >90%

High Strength Low Alloy Steel

Cold rolled HSLA (High Strength Low Alloy) steels are strengthened by a combination of precipitation hardening and grain size refining resulting in high strength with low alloy. Due to their fine grain microstructure and excellent weldability these grades are particularly suitable for structural components such as suspension systems and chassis and reinforcement parts.

HSLA steels offers good fatigue strength suitable for suspension arm, shock tower along with superior impact strength applicable for longitudinal beams cross members, reinforcements, etc. For their respective yield strength levels, these steels show excellent cold forming and low-temperature brittle fracture strength. The various HSLA grades are characterized by their yield strength.

Although the JSW HSLA grades match perfectly well to the designated EN standards, JSW generally offers tighter mechanical properties.

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Grades prEN 10268 : 2006 YS (N/mm2) trans. UTS (N/mm2) trans. El % A80 trans.
HC260LA 270-310 350-430 31-34
HC300LA 320-350 420-440 30-33
HC340LA 360-390 410-510 28-32
HC380LA 400-430 510-540 24-28
HC420LA 450-480 550-580 21-25

Typical Mechanical Properties of HSLA grades at JSW Steel

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Grades prEN 10268 : 2006 YS (N/mm2) trans. UTS (N/mm2) trans. El % A80 trans.
HC260LA 270-310 350-430 31-34
HC300LA 320-350 420-440 30-33
HC340LA 360-390 410-510 28-32
HC380LA 400-430 510-540 24-28
HC420LA 450-480 550-580 21-25

Notes

  • 1N/m m2 = 1MPa
  • Yield strength refers to the 0.2% proof strength for the product

Cold Rolled HC340LA Microstructure

Cold Rolled HC340LA Microstructure

*The service properties of HSLA Steel are guaranteed by the controlled manufacturing process. the controlled annealing cycle in particular ensures achievement of the Fine Grained (Ferrite + pearlite) microstructure and reproducibility of mechanical properties.

Bake Hardening Grades

JSW BH grades are best suited for the automobile components, which are put for the commercial paint baking operation. Some examples of these components are side, outer, inner body panels.

BH grades possesses higher yield and tensile strength than conventional low carbon steel, excellent formability (r & n-value) along with bake hardening strength of 35-50 MPa.

BH grades can replace lower strength material with thicker gauge and provide better fuel efficiency by decreasing the weight of the vehicle. It has better dent resistance than conventional low C steel confirming better safety of the automobiles and the passengers as well. The various BH grades are characterized by their yield strength as per EN standard .

BH Effect

BH Effect

The Mechanism and evaluating method of bake hardening in a tensile is illustrated in above figure

Cold Rolled HC220BH Microstructure

Cold Rolled HC220BH Microstructure

BH Grade Microstructure showing complete polygonal ferrite grains resulting in excellent drawability.

Bake hardening -IF steel having carbon content of <0.0035 wt% has very low yield strength initially. Small amount of carbon (approx 5 to 10ppm wt %) is intentionally left unfixed in steel solution by controlled Ti addition.

Following press forming via plastic deformation the induced dislocations results in work hardening.

The press formed components are heated at approx 1700C for 20mins during bake hardening process.

Through the paint baking process the solute carbon stabilizes the dislocations which were induced during work hardening by diffusing next to the core of a dislocation.

An additional stress is now required to promote the slip movement once mobile dislocations are pinned down by solute carbon after paint baking.

Therefore, a bake hardenable steel sheet exhibits a low yield strength value before press forming and a high yield strength value in a finished car component after paint baking.

Standard and Mechanical Properties prEN 10268:2006

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Grades prEN 10268 : 2006 YS (N/mm2) trans. UTS (N/mm2) trans. El % A80 trans. r min trans. n min trans. BH2 (MPa).
HC180B 180-230 300-360 ≥26 ≥1.6 ≥0.17 ≥35
HC220BH 220-270 340-400 ≥23 ≥1.5 ≥0.16 ≥35
HC260BH 260-300 370-430 ≥21 - ≥0.15 ≥35

Notes

  • 1N/mm2 = 1MPa
  • Yield strength refers to the 0.2% proof strength for the product.
  • JSW BH grades confirms Ageing Guarantee of 6 Months.