Introduction
309 s corresponding Chinese brand is 0 cr23ni13, American standard S30908 (American AISI, ASTM) .corrosion resistance, heat resistance are better than 0 cr19ni9.309 s is containing sulfur free cutting stainless steel.

It is a variation of 309 stainless steel  with lower carbon content. It is applied to the occasion. Low carbon content is made in the heat affected zone near the weld in the precipitation of carbide to a minimum,which may result in precipitation of carbide stainless steel inter-granular corrosion in some environments (welding erosion)

Technical Parameter

309S stainless steel
Standard	Grade	Chemical Composition %	Technique	Yied strength Mpa	Tensile strength Mpa	Elongation %	Hardness
GB	0Cr23Ni13	C≤0.08，Mn≤2.00， Si≤1.00，P≤0.045， S≤0.030，Cr 22.0~24.0, Ni 12.0~15.0	hot, cold rolled	≥205	≥520	≥40	HV≤200
USA	309S
JIS	SUS309S
German	/

Nominal diameter		Outside (mm)	Nominal wall thickness
			SCH5 S			SCH1 0S			SCH2 OS
N.B	NPS		Wall (mm)	WEIGHT （kg/m）		Wall (mm)	WEIGHT （kg/m）		Wall (mm)	WEIGHT （kg/m）
				Grade			Grade			Grade
				TP304 TP304L	TP316 TP316L		TP304 TP304L	TP316 TP316L		TP304 TP304L	TP316 TP316L
8	1/4"	13.72				1.65	0.5	0.5	2.24	0.64	0.64
10	3/8"	17.15				1.65	1.65	0.64	2.31	0.85	0.86
15	1/2"	21.34	1.65	0.81	0.81	2.11	1.01	1.02	2.77	1.28	1.29
20	3/4"	26.67	1.65	1.03	1.03	2.11	1.29	1.3	2.87	1.7	1.71
25	1"	33.4	1.65	1.31	1.31	2.77	2.11	2.13	3.38	2.53	2.54
32	1 1/4"	42.16	1.65	1.67	1.68	2.77	2.72	2.74	3.56	3.42	3.45
40	1 1/2"	48.26	1.65	1.92	1.93	2.77	3.14	3.16	3.68	4.09	4.11
50	2"	60.33	1.65	2.41	2.43	2.77	3.97	4	3.91	5.5	5.53
65	2 1/2"	73.03	2.11	3.73	3.75	3.05	5.32	5.35	5.16	8.72	8.78
80	3"	88.09	2.11	4.56	4.59	3.05	6.52	6.56	5.49	11.4	11.5
90	3 1/2"	101.6	2.11	5.23	5.23	3.05	7.49	7.54	5.74	13.7	13.8
100	4"	114.3	2.11	5.9	5.9	3.05	8.45	8.51	6.02	16.2	16.3
125	5"	141.3	2.77	9.56	9.56	3.4	11.7	11.8	9.55	22	22.1
150	6"	168.28	2.77	11.4	11.4	3.4	14	14.1	7.11	28.5	28.7
200	8"	219.08	2.77	14.9	14.9	3.76	20.2	20.3	8.18	43	43.2
250	10"	273.05	3.4	22.8	22.8	4.19	28.1	28.2	9.27	60.9	61.3
300	12"	323.85	3.96	31.6	31.6	4.57	36.3	36.6	9.52	74.5	75
350	14"	355.6	3.96	34.7	34.7	4.78	41.8	42
400	16"	406.4	4.19	42	42	4.78	47.8	48.1
450	18"	457.2	4.19	47.3	47.3	4.78	53.9	54.2
500	20"	508	4.78	59.9	59.9	5.54	69.3	69.8
550	22"	558.8	4.78	66	66	5.54	76.4	76.8
600	24"	609.6	5.54	83.4	119.5	6.35	95.4	96
750	30"	762	6.35	119.5	119.5	7.92	148.8	149.7

Seamless steel pipe
Steel ingots or solid tube through the perforation of the capillary, and then by hot-rolled, cold-rolled or cold dial made. with hollow cross-section, a large number of pipes for the transmission fluid. is generally molten state of the molten steel through the annular slit back out and then processed by the tensile molding process, so there is no weld. In terms of performance, especially pressure on the ability of welded steel pipe has greatly improved, it is often used for high-voltage equipment. Such as hydraulic equipment, piping connections.

Welded pipe
A steel or steel plate bending deformation into a circular and then welded into the surface of the steel pipe joints. Welded pipe used in the blank is steel or strip.The welding seam of welded steel pipe is the weak link, and the quality of weld is also the main factor affecting its overall performance. Welded steel pipe in the north of the China people living in general have had water pipes or heating pipes in the winter was the experience of cold explosion, where the explosion is generally weld.

Application
309S Generally used for furnace material, produced in 850 ℃ -- 1050 ℃ work of all kinds of heat-resistant artifacts, such as bracket, conveyor belts,annealing furnace cover, thermal cracking tubes, etc. Mainly used for free cutting and the surface which is bright and high clean demanding occasions