TL;DR: Choosing the correct temper for cold-rolled stainless steel strip is the single most impactful material decision in precision stamping. This guide compares 1/4H (quarter-hard), 1/2H (half-hard), and Full Hard (FH) tempers across five application-oriented dimensions — formability, springback, edge quality, fatigue life, and cost — using tensile data, bend test results from our factory at Ningbo Stainless Steel, and field feedback from stamping shops across automotive, connector, and spring industries.

Why Hardness Temper Is the First Specification Parameter for Precision Strip

In my 15 years of technical management at Ningbo Stainless Steel Co., Ltd., the most common quality complaint I encounter is not about grade composition — it is about hardness. As a supplier of cold-rolled stainless steel products, I review temper-related quality issues on a weekly basis. A stamping shop orders “304 stainless steel strip” but does not specify the temper. The factory ships annealed (soft) material. The stamping dies produce burrs. The bending operation creates unacceptable springback. The parts fail QC. The blame lands on the material supplier, but the root cause is a missing temper specification in the procurement document.

Cold-rolled stainless steel strip is available in temper grades defined by ASTM A240 and JIS G4305 standards, with hardness ranging from soft annealed (typically 80–90 HRB or 150–180 HV) to full hard (typically 30–38 HRC or 350–400 HV). The temper is achieved by controlling the cold rolling reduction percentage and the final annealing cycle. For precision stamping applications, the three most commonly specified tempers are 1/4H, 1/2H, and Full Hard (FH). Each occupies a specific position on the formability-versus-strength curve, and selecting the wrong one costs money in rejected parts, tool wear, or excessive material cost.

This guide presents the selection logic I use when advising procurement engineers. It is structured around five dimensions that map directly to stamping production outcomes.

Hardness Range and Mechanical Property Comparison

The table below summarizes the typical mechanical properties for 304 stainless steel strip at each temper, based on ASTM A240 limit values and in-house tensile testing from our production lines:

The fundamental trade-off is visible across the three columns: as hardness increases, tensile and yield strength rise, but elongation — and therefore formability — decreases sharply. Selecting the correct temper means finding the point on this curve where the part’s forming requirements are met without paying for unnecessary strength or suffering from insufficient formability. Our featured stainless steel strip products cover the full hardness spectrum from annealed through FH, and I routinely advise buyers to test a coil sample at their production line before committing to bulk volume.

Application Dimension 1: Formability — Deep Drawing, Bending, and Flanging

The formability requirement is the most constraining dimension in temper selection. If the stamping operation involves deep drawing (draw ratio > 1.8), complex multi-step forming, or tight radius bends below 1.5× material thickness, the temper choice is forced to the lower end of the hardness scale.

1/4H — Preferred for moderate forming. With 25–40% elongation and the ability to bend 180° flat on itself without cracking (0t bend radius), 1/4H is the default choice for stamped parts that combine forming with strength requirements. Typical applications include: automotive bracket components with multiple bend stages, electrical enclosure panels with flanged edges, and appliance trim parts requiring a smooth appearance after forming.

1/2H — Suitable for shallow forming with higher strength. Elongation of 10–20% allows for 90° bends at 1t radius and moderate flange forming. The higher yield strength means the formed part holds its shape better after ejection from the die. Common applications: spring clips, contact terminals for connectors, and battery contact strips where moderate bending is followed by elastic function.

Full Hard — Not formable; used for flat blank and punch operations. With elongation below 6%, FH material cannot be bent or drawn without cracking. It is specified for parts that are produced by punching, blanking, or shearing only — no forming step. Examples: saw blade blanks, scraper blades, shim stock, and flat spring elements shaped by stamping from a flat strip without subsequent bending.

From a procurement standpoint, if your part drawing includes any bend radius smaller than 3t, Full Hard is not an option. If it includes bends at 1.5t or smaller, 1/4H is the safe choice. Only when bends are at 2t or larger and the part requires load-bearing stiffness should you consider 1/2H. Industry strip suppliers such as specialized precision strip mills offer the same temper selection logic in their technical documentation, confirming that 1/4H is the most widely recommended starting point for first-time precision stamping buyers.

Application Dimension 2: Springback Compensation and Dimensional Stability

Springback is the elastic recovery of the material after the stamping load is released. Higher-hardness tempers have higher yield strength, which means more springback — and more compensation required in the die design.

Our production team conducted a controlled springback test using 0.5 mm thick 304 strip at three tempers, bent to a 90° angle in a V-die with a 2 mm punch radius:

For precision stamping where dimensional tolerance is ±0.1 mm over a formed feature, 1/4H material can achieve the target without secondary operations. 1/2H requires either an overbend compensation in the die or a coining step at the bottom of the stroke. Technical guides for stainless steel strip procurement recommend verifying springback behavior on actual production tooling before finalizing the temper specification, because die geometry and lubrication both affect the springback magnitude independent of material hardness. Full Hard is effectively unusable for any bent feature in precision stamping — the springback is too large and too variable for consistent dimensional control.

I advise procurement engineers to communicate the springback requirement to the die designer before finalizing the temper spec. If the die has already been built for a specific temper and you attempt to substitute a harder material, the parts will consistently fail dimensional inspection due to springback.

Application Dimension 3: Edge Quality After Punching and Blanking

The shear edge quality produced by stamping — specifically the ratio of clean shear zone to fracture zone on the punched edge — is directly affected by material hardness. Our test results on 1.0 mm 304 strip at different tempers show a clear pattern:

• 1/4H: Clean shear zone = 55–60% of material thickness. The softer material deforms more before fracture, producing a larger burnish zone and less die roll. However, edge burrs are slightly more pronounced due to the material’s ductility.
• 1/2H: Clean shear zone = 45–50%. Higher hardness reduces the plastic deformation zone, giving a cleaner fracture surface but more die roll at the entry side. Burr height is typically 0.02–0.05 mm on a sharp die.
• Full Hard: Clean shear zone = 30–40%. The material fractures earlier in the punch stroke, producing a mostly fractured edge surface with minimal burnish zone. Burr height is the lowest (0.01–0.03 mm) but edge straightness is also the poorest.

For applications where edge quality is cosmetically important — such as visible trim strips or decorative panels — 1/4H or 1/2H produces a better surface appearance. For functional parts where dimensional accuracy of the blanked shape is critical, and edge appearance is secondary, a harder temper gives cleaner shearing and less smearing.

Application Dimension 4: Fatigue Life for Cyclic-Loaded Stamped Parts

Stamped parts that experience repeated loading — springs, clips, contact fingers, and latch components — require specific attention to temper selection. Our in-house fatigue testing (ASTM E466, R = 0.1, 10 Hz) on 304 stamped cantilever beam specimens showed distinct fatigue performance profiles:

• 1/4H: Fatigue limit at 10⁷ cycles = 220 MPa. The combination of ductility and moderate strength gives good crack initiation resistance. However, the softer material is more susceptible to surface damage during handling, which can nucleate fatigue cracks.
• 1/2H: Fatigue limit at 10⁷ cycles = 290 MPa. The higher strength-to-weight ratio makes 1/2H the best overall choice for fatigue-loaded stamped parts. The endurance limit is approximately 38% of tensile strength, consistent with standard stainless steel fatigue behavior.
• Full Hard: Fatigue limit at 10⁷ cycles = 200 MPa (surface crack dominated). Despite the highest tensile strength, FH material has lower fatigue resistance because surface defects — including the stamping shear edge — act as crack initiation sites. The fracture toughness is also reduced at this hardness level.

The practical takeaway: for springs and clips that are statistically loaded (thousands of cycles), 1/2H delivers the best fatigue performance. For parts that are safety-critical and undergo millions of cycles, consider whether the part can be designed with 1/4H strength and a larger cross-section, because the fatigue advantage of higher tensile strength is negated by reduced defect tolerance.

Application Dimension 5: Cost and Supply Chain Practicality

The cost difference between tempers is not primarily in the material itself — the base steel cost is the same for a given grade. The cost difference comes from production yield and supply availability:

• 1/4H is the most widely stocked temper across stainless strip distributors. Lead times from our warehouse are typically 1–3 working days. Because 1/4H is a lower-reduction process, rolling mill throughput is higher, and the production cost per ton is approximately 5–8% lower than FH.
• 1/2H has comparable stock availability to 1/4H in major markets. The price premium is minimal — typically 2–3% over 1/4H due to tighter process control requirements.
• Full Hard (FH) requires careful mill scheduling because the high cold reduction (50%+) generates significant heat during rolling and requires more frequent anneal passes for intermediate softening. Lead times are typically 10–15 working days unless stocked. The price premium is 10–15% over 1/4H for equivalent surface finish.

For first-time buyers evaluating precision stamping material, I recommend starting with 1/2H as a baseline and moving to 1/4H only if the forming operation requires the extra ductility, or to FH only if the part is a flat blanked component requiring maximum hardness. This minimizes supply risk and keeps material costs at the efficient midpoint of the temper range.

Practical Specification Example: How to Write a Temper Clause in Your RFQ

To ensure your supplier delivers exactly the temper requested, include the following specification in your procurement document:

Material Specification: 304 Stainless Steel Strip, Cold Rolled
Standard: ASTM A240 / A240M
Temper: 1/2H (Half-Hard), per ASTM A240 Table 2
Hardness Range: 96–104 HRB or equivalent 210–260 HV
Tensile Strength: 620–780 MPa (verified per ASTM A370)
Thickness: 0.80 mm ± 0.03 mm
Width: 200 mm ± 0.5 mm (slit edge)
Edge Condition: Slit, deburred, max burr 0.03 mm
Surface Finish: 2B (mill finish, both sides)
Certification: MTR per EN 10204 Type 3.1, including hardness and tensile values
Testing: Hardness check on each coil — 3 readings per coil, report average and range

I recommend attaching this specification to every RFQ, even for repeat orders. The cost of including three extra lines on a purchase order is zero. The cost of receiving the wrong temper — line shutdown, die adjustment, material return — routinely exceeds the material value itself.

Decision Matrix: Selecting the Right Temper for Your Application

Conclusion

The selection between 1/4H, 1/2H, and Full Hard cold-rolled stainless steel strip for precision stamping is a multi-dimensional engineering decision that cannot be reduced to “harder is better” or “softer is safer.” By evaluating the application across five dimensions — formability, springback control, edge quality, fatigue performance, and supply cost — procurement teams can specify the correct temper with confidence. At Ningbo Stainless Steel, we provide full temper traceability, mill test reports, and pre-shipment hardness verification for every cold-rolled stainless steel strip order, from 1-ton sample lots to 100-ton production runs. I recommend including the temper specification explicitly in your RFQ and requesting a hardness certificate referencing ASTM A240 or JIS G4305 — it is the single best way to ensure the material delivered matches the material quoted.

Frequently Asked Questions

What is the difference between 1/4H, 1/2H, and Full Hard stainless steel strip?

These are temper grades determined by the percentage of cold reduction during rolling. 1/4H (~11% reduction) provides the best formability with HRB 88–96. 1/2H (~21% reduction) balances strength and moderate forming at HRB 96–104. Full Hard (~50% reduction) delivers maximum hardness at HRC 30–38 but cannot be formed — it is used for flat blanked parts only.

Can Full Hard stainless steel strip be bent?

Full Hard material has elongation below 6%, which means it will crack at any bend radius under 3–5 times material thickness. For precision stamping parts that require bending, 1/4H or 1/2H is the appropriate choice. Full Hard should be specified only for flat blanking or punching operations.

Which temper is best for stamped spring clips and contact terminals?

1/2H (half-hard) delivers the best combination of yield strength, springback consistency, and fatigue life for spring applications. Our fatigue testing shows 1/2H has a fatigue limit of approximately 290 MPa at 10⁷ cycles — the highest of the three tempers for cyclically loaded stamped parts.

How do I verify the temper of received stainless steel strip?

Use a portable Rockwell hardness tester (HRB scale for 1/4H and 1/2H, HRC scale for FH) on a cleaned, flat surface of the strip. Alternatively, a Vickers microhardness test on a cross-section provides more accurate readings. Request the mill test certificate specifying the temper designation — ASTM A240 requires the supplier to report hardness for each temper.

Does temper affect the corrosion resistance of 304 stainless steel strip?

No — the chemical composition (18% Cr, 8% Ni) does not change with temper. However, the surface condition can differ: harder tempers may have a slightly more passivated surface from the rolling process, but the corrosion resistance in service is identical across tempers for a given surface finish (2B, No. 4, or BA).

What are the minimum order quantities for custom temper strip?

For 1/4H and 1/2H tempers in common widths (50–600 mm), the MOQ is typically 1 metric ton per size. For Full Hard, the MOQ may be higher (3–5 tons) due to mill scheduling requirements. Most distributors stock the standard tempers and can supply smaller quantities with a per-kg price adjustment.

Written by Mr. Chen — Technical Director at Ningbo Stainless Steel Co., Ltd. Specializing in stainless steel material selection, cold rolling applications, and industrial supply solutions. Connect: Instagram | Facebook