③ 标准/对比页
S355JR vs S355J2: Same Strength, Different Cold Rating
S355JR and S355J2 are quality variants of the same EN 10025-2 structural grade: identical 355 MPa minimum yield and 470–630 MPa tensile band. The single letter changes the Charpy requirement — 27 J at +20 ℃ for JR, at −20 ℃ for J2 — which is why the choice is driven by service temperature, not by strength.
One Grade, Three Impact TiersEN 10025-2 splits S355 into JR, J0 and J2 by Charpy temperature: 27 J at +20 ℃, 0 ℃ and −20 ℃ respectively. Strength does not move — yield stays at 355 MPa (≤16 mm) and tensile at 470–630 MPa across the family. The letters are about verified toughness in the cold, nothing else.
Where JR Is EnoughJR suits normal ambient service: building frames, platform structures and machinery bases installed and working above freezing. If the lowest service temperature stays mild and the design carries no cold-room, arctic or impact-critical feature, JR is the economical pick and the most widely stocked S355 variant.
When J2 Earns Its KeepJ2 carries verified 27 J at −20 ℃, which outdoor cranes, towers, bridge components and cold-region structures typically demand. J2 is also commonly ordered in normalized condition, which many designers pair with heavier welded sections. Expect a modest price step and slightly longer rolling lead times versus JR.
Chemistry and Z-QualityBoth variants share the EN 10025-2 analysis window — carbon up to 0.24 % with CEV around 0.45 depending on thickness — so welding procedures do not change between them. Where through-thickness properties are specified, both can be supplied with Z-quality under EN 10164; add it to the PO rather than assuming it.
Ordering NotesState the exact variant (JR/J0/J2), thickness list and any Z requirement on the RFQ. Yunhao exports the S355 family with EN 10204 mill test certificates; typical supply is 25 t MOQ, 15–30 days from Tianjin or Qingdao. If drawings switch variants mid-project, we re-quote rather than assume equivalence.
| Item | S355JR | S355J2 |
|---|---|---|
| Standard | EN 10025-2 | EN 10025-2 |
| Yield ReH (≤16 mm) | ≥355 MPa | ≥355 MPa |
| Tensile Rm | 470–630 MPa | 470–630 MPa |
| Charpy KV min | 27 J at +20 ℃ | 27 J at −20 ℃ |
| Typical delivery | as-rolled | often normalized |