JIS Standards Boiler and Heat Exchanger Steel Tube Standard JIS G3461 JIS G3462 Application It is used for boiler and heat exchanger inside & outside tube. Main Steel Tube Grades STB340, STB410, STB510, STBA12, STBA13, STBA20, STBA22, STBA24 Chemical Composition

Standard	Steel Grade	Chemical Composition %
		C	Si	Mn	P	S	Cr	Mo
JIS G3461	STB340	≤0.18	≤0.35	0.30-0.60	≤0.035	≤0.035	/	/
	STB410	≤0.32	≤0.35	0.30-0.80	≤0.035	≤0.035	/	/
	STB510	≤0.25	≤0.35	1.00-1.50	≤0.035	≤0.035	/	/
JIS G3462	STBA12	0.10-0.20	0.10-0.50	0.30-0.80	≤0.035	≤0.035	/	0.45-0.65
	STBA13	0.15-0.25	0.10-0.50	0.30-0.80	≤0.035	≤0.035	/	0.45-0.65
	STBA20	0.10-0.20	0.10-0.50	0.30-0.60	≤0.035	≤0.035	0.50-0.80	0.40-0.65
	STBA22	≤0.15	≤0.50	0.30-0.60	≤0.035	≤0.035	0.80-1.25	0.45-0.65
	STBA24	≤0.15	≤0.50	0.30-0.60	≤0.030	≤0.030	1.90-2.60	0.87-1.18

  Mechanical Properties

Standard	Steel Grade	Mechanical Properties
		Tensile Strength MPa	Yield Strength MPa	Elongation %
JIS G3461	STB340	≥340	≥175	≥35
	STB410	≥410	≥255	≥25
	STB510	≥510	≥295	≥25
JIS G3462	STBA12	≥380	≥205	≥30
	STBA13	≥410	≥205	≥30
	STBA20	≥410	≥205	≥30
	STBA22	≥410	≥205	≥30
	STBA24	≥410	≥205	≥30