Steel equivalents / Seamless / welded carbon steel pipe (A106 Gr B / API 5L Gr B / P235TR1-P265TR1 / STPG370 / SPPS380)

STPG370 (anciennement STPG38)

JPApproximate match

JIS · JIS G3454:2018

Family of seamless or welded carbon steel pipes used to convey fluids (steam, water, hydrocarbons, compressed air) at moderate pressure and temperature, generally up to 350-400°C. The industry's historical reference: ASTM A106 Grade B and API 5L Grade B in the United States, with close equivalents in Europe (EN 10216-1), Japan (JIS G3454) and South Korea (KS D3562, harmonized with the Japanese standard).

Equivalents by yield strength proximity

Grade	Region	Standard	Re (MPa)	Rm (MPa)	Delta
STPG370 (anciennement STPG38)	JP	JIS G3454:2018	215	≥370	reference
SPPS380 (anciennement SPPS38)	KR	KS D3562	220	≥380	+2%
P235TR1 (1.0254)	EU	EN 10216-1:2013	235	360–500	+9%
Neighboring grades — different strength
A106 Grade B	US	ASTM A106/A106M-19 (ASME SA-106)	240	≥415	+12%
API 5L Grade B / L245	US	API Spec 5L (46e éd.), PSL1	245	≥415	+14%
P265TR1 (1.0258)	EU	EN 10216-1:2013	265	410–570	+23%

Chemical composition (wt%)

Grade	C	Mn	Si	P	S	Cr	Ni	Mo	Cu	V
STPG370 (anciennement STPG38)	≤0.25	0.3–0.9	≤0.35	≤0.04	≤0.04	—	—	—	—	—
SPPS380 (anciennement SPPS38)	≤0.25	0.3–0.9	≤0.35	≤0.04	≤0.04	—	—	—	—	—
P235TR1 (1.0254)	≤0.16	≤1.2	≤0.35	≤0.025	≤0.02	≤0.3	≤0.3	≤0.08	≤0.3	≤0.02
A106 Grade B	≤0.3	0.29–1.06	≥0.1	≤0.035	≤0.035	≤0.4	≤0.4	≤0.15	≤0.4	≤0.08
API 5L Grade B / L245	≤0.28	≤1.2	—	≤0.03	≤0.03	≤0.5	≤0.5	≤0.15	≤0.5	—
P265TR1 (1.0258)	≤0.2	≤1.4	≤0.4	≤0.025	≤0.02	≤0.3	≤0.3	≤0.08	≤0.3	≤0.02

Note: The Japanese reference grade for pressure pipe up to 350°C. A simpler specification than its US/EU equivalents (no explicit Cr/Mo/Ni/Cu ceilings), with quality control relying mainly on guaranteed mechanical properties. For wall thickness <8mm, minimum elongation decreases by 1.5 points per mm of reduction.

Values compiled from public sources for guidance only — always verify against the official standard before use in design or fabrication.