The high-strength austenitic stainless for springs and connectors — SUS301 per JIS G4304, equivalent to GB 12Cr17Ni7 and ASTM S30100. C ≤0.15%, Cr 16.0–18.0%, Ni 6.0–8.0%. Cold-worked to tensile up to 1500 MPa (SH condition) for springs,发条, electronic connectors and slide rails.
SUS304 (18Cr/8Ni) has stable austenite — max tensile ~750–850 MPa, non-magnetic, better corrosion resistance. SUS301 (17Cr/7Ni) has metastable austenite — cold working triggers martensite, tensile to 1300–1500 MPa, weakly magnetic. SUS301 for high-strength springs; SUS304 when corrosion/non-magnetic matters more.
SUS301 for high-strength springs; SUS304 for corrosion-resistant, non-magnetic parts.SUS304-CSP reaches ~900–1100 MPa but can't match SUS301's 1300–1500 MPa (stable austenite doesn't transform). SUS301-CSP standard for high-strength stainless springs (发条, contacts); SUS304-CSP when lower strength is OK and better corrosion/non-magnetic required. Both share temper designations (1/2H, 3/4H, FH).
SUS301-CSP for max strength; SUS304-CSP for better corrosion at lower strength.17-7PH reaches 1500–1900 MPa after aging (475°C), better corrosion, but requires two-step heat treatment and costs significantly more. SUS301 achieves high strength purely by cold rolling — no heat treatment, lower cost, simpler processing. SUS301 for high-volume cost-sensitive parts; 17-7PH for aerospace/high-end.
SUS301 for cost-effective high-strength; 17-7PH for aerospace-grade strength and corrosion.| Element | SUS301 (JIS G4304) % | 12Cr17Ni7 (GB/T 4239) % | S30100 (ASTM A666) % | Role |
|---|---|---|---|---|
| Carbon (C) | ≤ 0.15 | ≤ 0.15 | ≤ 0.15 | Strengthens; promotes martensite formation during cold work |
| Silicon (Si) | ≤ 1.00 | ≤ 1.00 | ≤ 1.00 | Deoxidizer; solid-solution strengthening |
| Manganese (Mn) | ≤ 2.00 | ≤ 2.00 | ≤ 2.00 | Stabilizes austenite; deoxidizer |
| Phosphorus (P) | ≤ 0.045 | ≤ 0.045 | ≤ 0.045 | Residual; controlled for formability |
| Sulfur (S) | ≤ 0.030 | ≤ 0.030 | ≤ 0.030 | Residual; controlled for surface quality |
| Chromium (Cr) | 16.0 – 18.0 | 16.0 – 18.0 | 16.0 – 18.0 | Corrosion resistance (passive Cr₂O₃ film); promotes martensite |
| Nickel (Ni) | 6.0 – 8.0 | 6.0 – 8.0 | 6.0 – 8.0 | Stabilizes austenite; lower than SUS304 → metastable → work-hardens |
Reference: JIS G4304; GB/T 4239; ASTM A666. Values typical per standard, actual confirmed on MTC. No Mo added — corrosion resistance good for atmospheric/mildly corrosive environments, below SUS316.
| Temper | Tensile (typ.) | Yield (typ.) | Elongation (typ.) | Hardness (typ.) | Typical use |
|---|---|---|---|---|---|
| Annealed (A) | ≥ 520 MPa | ≥ 205 MPa | ≥ 40% | ≤ 220 HB | Deep drawing, severe forming |
| 1/4 Hard (1/4H) | ~800 – 1,000 MPa | ~500 – 700 MPa | ~20 – 30% | ~250 – 300 HV | Moderate forming, general parts |
| 1/2 Hard (1/2H) | ~1,000 – 1,200 MPa | ~750 – 950 MPa | ~10 – 20% | ~300 – 360 HV | General springs, connectors, forming |
| 3/4 Hard (3/4H) | ~1,200 – 1,350 MPa | ~950 – 1,100 MPa | ~5 – 12% | ~360 – 420 HV | High-strength springs, simple forming |
| Full Hard (FH) | ~1,300 – 1,450 MPa | ~1,100 – 1,250 MPa | ~3 – 8% | ~420 – 480 HV | Springs,发条, blanked parts (minimal forming) |
| Special Hard (SH / EH) | ~1,400 – 1,500+ MPa | ~1,200 – 1,350 MPa | ~2 – 5% | ~480 – 550 HV | Highest-strength springs, flat springs, contacts |
Values typical per JIS G4304 / ASTM A666; actual confirmed on MTC. Mechanical properties vary with strip thickness — thinner strip typically achieves higher tensile at the same temper. SUS301 becomes weakly magnetic after cold working due to strain-induced martensite. For parts requiring non-magnetic behavior, use SUS304 instead.
| Standard | Grade | Cr (%) | Ni (%) | Notes |
|---|---|---|---|---|
| JIS G4304 / G4305 (Japan) | SUS301 | 16.0 – 18.0 | 6.0 – 8.0 | Base reference |
| GB/T 4239 / GB/T 3280 (China) | 12Cr17Ni7 (formerly 1Cr17Ni7) | 16.0 – 18.0 | 6.0 – 8.0 | Identical chemistry |
| ASTM A666 / AISI (USA) | 301 (UNS S30100) | 16.0 – 18.0 | 6.0 – 8.0 | Identical chemistry |
| EN 10088-2 / DIN (Europe) | X10CrNi18-8 (1.4310) | 16.0 – 19.0 | 6.0 – 9.0 | Slightly wider ranges; same family |
Equivalents approximate. Temper designation systems differ between standards (JIS 1/4H–SH vs. EN 1.4310 temper classes) — confirm mechanical properties, not just grade name, for your application.
0.10–1.0 mm FH/SH strip, blanked into flat and leaf springs. Tensile 1300–1500 MPa gives spring force and fatigue resistance in a stainless that won't rust. Used in automotive (brake return springs, sensor springs), appliances (door latch springs) and industrial equipment. See our spring steel guide.
0.08–0.30 mm FH/SH strip, coiled into spiral mainsprings for clocks, watches, toys, retractable cords and timers. Ultra-high tensile (1400–1500+ MPa) plus ~2–5% elongation allows tight coiling without cracking. Corrosion resistance prevents rust during storage — an advantage over carbon steel发条. Precision thickness ±0.003 mm for consistent force.
0.10–0.40 mm 1/2H–FH strip, stamped into connector contacts, terminal pins, relay springs and switch contacts. High yield (750–1250 MPa) maintains normal force over millions of mating cycles. Corrosion resistance prevents contact degradation in humid environments. Often tin/nickel/gold plated at the contact zone for conductivity and wear.
0.30–1.50 mm 1/2H–FH strip, roll-formed into linear slide rails, drawer slides, telescopic channels and guide ways. High strength (1000–1400 MPa) gives stiffness and load capacity; stainless prevents rust in kitchen, bathroom, medical and outdoor applications. Good formability allows complex profiles with tight bend radii. See precision components.
SUS301 achieves its high strength through cold rolling — no quenching or aging is involved.
Electric arc or induction melting, AOD refining to control C ≤0.15%, continuous casting. Strict Cr (16–18%) and Ni (6–8%) control ensures metastable austenite for work-hardening response. Too much Ni stabilizes austenite; too little causes ferrite.
Slabs reheated to 1100–1250°C, hot rolled to 2.0–5.0 mm coil, solution annealed at 1010–1150°C and rapidly cooled to dissolve carbides and produce fully austenitic, soft (≤220 HB) microstructure. Starting condition for cold rolling.
Reduction determines temper: 1/4H (~15–25%), 1/2H (~25–35%), 3/4H (~35–45%), FH (~45–55%), SH (~55–65%+). Cold rolling transforms metastable austenite to strain-induced martensite — boosting strength from ~520 MPa (annealed) to 1500+ MPa (SH). Sendzimir/cluster mills for thin precision strip.
Coils slit to width (from 5 mm), tension-leveled, edge-conditioned (rounded/deburred). Finishes: 2B (standard), BA (bright/mirror), polished. 2B or BA standard for connectors and springs. Thickness tolerance ±0.003–0.010 mm. No heat treatment after cold rolling — used as-cold-worked.
Include thickness × width, quantity, temper (1/4H / 1/2H / 3/4H / FH / SH), surface finish and destination port. Reply within one working day.