How to read this table
Mechanical property ranges are from mill specifications, averaged across the major Asian and European suppliers we buy from (Baosteel, POSCO, thyssenkrupp, ArcelorMittal). Actual batch data varies by ±5 % on yield and ±3 % on tensile — we supply the specific mill certificate with every shipment of a stamped part. Elongation figures are A50 longitudinal per ISO 6892-1.
Relative cost is normalised to DP590, representing both the raw coil price and a rough factor for stamping-line complexity (die wear, press tonnage, cycle adjustments). A DP1180 part is not just 1.55× the material cost of a DP590 part — it's also a slower stamping cycle and faster die wear, both already included in that factor.
Full property table — 8 grades
| Grade | Yield | Tensile | Elongation | Hardness | Formability | Weldability | Rel. cost |
|---|---|---|---|---|---|---|---|
DP590 Dual-Phase 590 Inner panels, reinforcements, mid-car structure. | 340 – 420 MPa | ≥ 590 MPa | ≥ 20 % | ~190 HB | Excellent — deep draw, stretch forming | Excellent (spot, MIG, laser) | 1.0× baseline |
DP780 Dual-Phase 780 B-pillar inner, roof rails, crash boxes. The workhorse HSS. | 450 – 550 MPa | ≥ 780 MPa | ≥ 15 % | ~240 HB | Good — needs larger radii, higher springback | Good (HAZ softening ~10 %) | 1.2× |
DP980 Dual-Phase 980 Bumper beams, side-impact beams, seat frames. | 550 – 700 MPa | ≥ 980 MPa | ≥ 10 % | ~290 HB | Moderate — flat parts / simple bends only | Fair (HAZ softening 15–20 %) | 1.35× |
DP1180 Dual-Phase 1180 A-pillar outer, roof bow, intrusion bars. Weight-critical crash. | ≥ 950 MPa | ≥ 1180 MPa | ≥ 5 – 8 % | ~350 HB | Limited — nearly flat parts, generous radii | Challenging (cracking risk, preheat) | 1.55× |
22MnB5 (PHS) Press-Hardened Steel, boron A/B-pillar, tunnel, rocker panel in EVs and modern crash-heavy cars. | ~400 MPa (soft) / ≥ 1100 MPa (hot-stamped) | ~600 MPa (soft) / 1500 – 2000 MPa (hot-stamped) | ~25 % (soft) / 5 – 7 % (hardened) | ~480 HB hardened | Formed soft, hardened in press — complex geometries possible | Requires coating-compatible spot welding (Usibor AlSi) | 1.7× (tooling and process heavy) |
304 Stainless 304 / 1.4301 austenitic Corrosion-critical, food contact, exhaust, medical housings. | ~215 MPa | ≥ 515 MPa | ≥ 40 % | ~200 HB (cold-rolled) | Excellent — deep draw, stretch, bend | Excellent (all processes) | 3.5 – 4.0× vs DP590 |
316L Stainless 316L / 1.4404 low-C austenitic Medical implants, marine, chemical — when 304 isn't enough. | ~170 MPa | ≥ 485 MPa | ≥ 40 % | ~185 HB | Excellent | Excellent (preferred for welded assemblies) | 4.5× |
S355 / S45C Mild / medium-C structural Non-crash structure, frames, jigs, fixtures. Cheapest baseline. | 355 – 540 MPa | 490 – 750 MPa | ≥ 18 % | ~180 HB | Good | Excellent (no preheat below t=25 mm) | 0.7× |
Picking a grade — the decision logic we use
The honest way to spec a part is to work backwards from crash performance and stamping feasibility, not forward from a weight target. An overly optimistic grade callout — "let's use DP1180, it's the strongest" — is the most common reason a quote gets rejected on DFM. The sections below are how we walk customers through grade selection in the first engineering call.
Start with elongation, not tensile
Stamping failures show up as splits and wrinkles. Both are governed by elongation and the n-value of the steel, not by tensile strength. DP1180 has ≥ 5 % elongation — enough for a bend around a 5× thickness radius, not enough for a deep-draw with 2× thickness side walls. If your part has any deep-draw geometry, start at DP780 (15 %) or DP590 (20 %) and drop down only if crash loads demand it.
Weight savings are modest until you cross 1000 MPa
Replacing DP590 with DP780 in a bracket lets you thin from 2.0 mm to ~1.8 mm for similar load capacity — 10 % weight saved. Replacing DP590 with DP1180 gets you to 1.4 mm — 30 % saved. But the 1.4 mm part is stiffer in bending (good), and weaker in elongation (bad), so the redesign often requires added ribs or a larger section, clawing back some of the weight. In practice we see DP780 take the most weight honestly, DP1180 take more only when combined with topology redesign.
Coating choice matters as much as grade
Automotive HSS ships in four common coating systems: GA (galvanneal, zinc-iron alloy), GI (hot-dip galvanised), EG (electrogalvanised), and Usibor (aluminium-silicon for 22MnB5 hot stamping). GA is standard for BIW exposed to cataphoretic paint. GI gives better scratch resistance but harder spot welding. Usibor is required for 22MnB5 parts that need to survive austenitising without scaling. Specify the coating explicitly — we cannot swap coatings in quotation without re-running the spot-weld parameter set.
When you shouldn't use steel at all
Aluminium 6022 or 6014 hits similar crash performance at 60 % the weight for non-battery parts and has become standard in hood, door and trunk outer panels of EVs. For a structural crash part in the battery frame, DP780 or 22MnB5 hot-stamped is cheaper per function and easier to weld into the existing body. If you're sending a drawing that specifies DP590 in a door outer, ask us whether an aluminium variant would win on total cost — we run both.
What we actually stock
- DP590, DP780, DP980, DP1180 — 0.6 mm to 3.0 mm gauge, GA and GI coatings. Same-week coil availability.
- 22MnB5 (Usibor 1500, Ductibor 500) — we outsource hot-stamping to a partner line in Guangzhou; cold blanking and post-stamp trimming done in-house.
- 304 / 316L / 321 stainless — 0.5 mm to 10 mm, sheet and plate, 2B and BA finishes.
- Mild steel S45C, S355, SPCC — commodity steel, fast ship, for non-crash structure and fixtures.
If you need a grade outside this list — high-manganese TWIP, martensitic MS1300, bake-hardenable BH-series — ask at quote time. We have relationships with Asian mills that cover most automotive-spec chemistries with a 2–3 week coil lead.