Certified Delivery Condition: EN 10132-4 (+QT)

Continuous Hardening and Tempering Metallurgical Process

Hardening and Tempering (+QT) is an automated thermal process that transforms cold-rolled strip steel into a high-tensile, resilient spring material through controlled austenitic heating followed by rapid quenching into martensite and precise reheating (tempering). This delivers high elastic yield strength, fatigue endurance, and wear resistance without post-stamping heat treatment.

All hardening lines utilize inert protective atmospheres to prevent surface decarburization, ensuring consistent hardness across every coil length and width according to EN 10132-4, DIN 17222, and ASTM A684 specifications.

Standard Grades, Chemical Composition & Mechanical Properties

Complying with EN 10132-4, DIN 17222, and international equivalents

Grade (EN / IS / W-Nr)	%C	%Si	%Mn	%S	%P	%Cr	%V	%Ni	Hardness Delivery	Tensile Rm (MPa)
C55S / C-55 (1.1204)	0.50 - 0.60	0.10 - 0.35	0.50 - 0.65	≤ 0.030	≤ 0.030	-	-	-	40 - 48 HRC (390 - 485 HV)	1250 - 1550 MPa
C67S / C-65 (1.1231)	0.60 - 0.70	0.10 - 0.35	0.50 - 0.65	≤ 0.030	≤ 0.030	-	-	-	42 - 50 HRC (415 - 510 HV)	1300 - 1600 MPa
C75S / C-75 / C-80 (1.1248)	0.70 - 0.85	0.10 - 0.35	0.50 - 0.80	≤ 0.030	≤ 0.030	-	-	-	44 - 52 HRC (430 - 540 HV)	1400 - 1700 MPa
C85S / C-85 (1.1269)	0.80 - 0.90	0.10 - 0.35	0.40 - 0.70	≤ 0.030	≤ 0.030	-	-	-	45 - 53 HRC (445 - 560 HV)	1420 - 1750 MPa
C100S / C-98 (1.1274)	0.90 - 1.05	0.10 - 0.35	0.50 - 0.80	≤ 0.030	≤ 0.030	-	-	-	46 - 54 HRC (460 - 580 HV)	1450 - 1800 MPa
50CrV4 / 50Cr4V2 (1.8159)	0.47 - 0.55	0.10 - 0.35	0.70 - 1.10	≤ 0.025	≤ 0.025	0.90 - 1.20	0.10 - 0.25	-	44 - 52 HRC (430 - 540 HV)	1400 - 1750 MPa
75Ni8 (1.5634)	0.72 - 0.80	0.15 - 0.35	0.30 - 0.50	≤ 0.025	≤ 0.025	≤ 0.15	-	1.80 - 2.20	44 - 50 HRC (430 - 510 HV)	1350 - 1650 MPa

International Standard Compliance

Manufactured and inspected under EN 10132-4 (Cold rolled narrow steel strip for heat treatment), DIN 17222 (Cold rolled spring steel), and ASTM A684 with full Mill Test Certificates (MTC).

View Grade Equivalents Table →

“Every coil of hardened and tempered strip steel leaving our facility is verified for surface finish, decarburization depth, flatness, and exact Rockwell hardness. Precision strip steel is an engineering commitment where consistency directly dictates our clients' component longevity.”

Physical Specifications & Tolerances

Thickness Range	0.05 - 4.00 mm (tolerances to ±0.005 mm)
Width Range	6 - 550 mm (slit width tolerances to ±0.02 mm)
Hardness Delivery Range	30 HRC Min up to 58 HRC Max (pre-tempered to customer specification)
Surface Finish	Bright polished, Blue (annealed tempered), Brown & Grey
Edge Condition	One or both sides edge-rounded (No. 1), square (No. 3), chamfered, or deburred sheared edge
Manufacturing Standards	EN 10132-4, DIN 17222, ASTM A684, IS 2507, ISO 9001:2015

Form of Supply & Packaging

Materials are supplied in precision-wound slit coils. Inner diameters (ID) of 300 mm, 400 mm, or 500 mm and customized outer diameters (OD) are maintained upon specification.

Material can also be supplied in cut-to-length (CTL) straight lengths from 100 mm to 4000 mm with precision shearing.

Export Packaging: Coils are treated with rust-preventive oil, wrapped in multi-layer VCI anti-corrosion film, and strapped onto heat-treated wooden pallets for global sea freight.