Introduction
2205 duplex stainless steel standard: ASTM A240/A240M--01 chromium 2205 duplex stainless steel alloy is a 22%, 2.5% 4.5%-NI-n alloy composition Mo and duplex stainless steels. It has high strength, good toughness and good global and local resistance to stress corrosion.
2205 duplex stainless steel yield strength of austenitic stainless steel is twice times, this feature enables designers to design products reduce the weight, price advantage over the 316,317L. This alloy is suitable within the temperature range-50 ° F/600 ° f. Exceeding this temperature range of application, this alloy can also be considered, but there are some limitations, especially when applied to welded structures.

Corrosion Resistance
Grade 2205 stainless steel exhibits excellent corrosion resistance, much higher than that of grade 316. It resists localized corrosion types like intergranular, crevice and pitting. The CPT of this type of stainless steel is around 35°C. This grade is resistant to chloride stress corrosion cracking (SCC) at temperatures of 150°C. Grade 2205 stainless steels are apt replacements to austenitic grades, especially in premature failure environments and marine environments.

Heat Resistance
The high oxidation resistance property of Grade 2205 is marred by its embrittlement above 300°C. This embrittlement can be modified by a full solution annealing treatment. This grade performs well at temperatures below 300°C.

Heat Treatment
The best suited heat treatment for this grade is solution treatment (annealing), between 1020 - 1100°C, followed by rapid cooling. Grade 2205 can be work hardened but cannot be hardened by thermal methods.

Welding
Most standard welding methods suit this grade, except welding without filler metals, which results in excess ferrite. AS 1554.6 pre-qualifies welding for 2205 with 2209 rods or electrodes so that the deposited metal has the right balanced duplex structure.
Adding nitrogen to the shielding gas ensures that adequate austenite is added to the structure. The heat input must be maintained at a low level, and the use of pre or post heat must be avoided. The co-efficient of thermal expansion for this grade is low; hence the distortion and stresses are lesser than that in austenite grades.

Machining
The machinability of this grade is low due to its high strength. The cutting speeds are almost 20% lower than that of grade 304.

Fabrication
The fabrication of this grade is also affected by its strength. Bending and forming of this grade requires equipment with larger capacity. Ductility of grade 2205 is lesser than austenitic grades; therefore, cold heading is not possible on this grade. In order to carry out cold heading operations on this grade, intermediate annealing should be carried out.

Technical Parameter

2205 stainless steel
Standard	Grade	Chemical Composition %	Technique	Yied strength Mpa	Tensile strength Mpa	Elongation %	Hardness
GB	00Cr24Ni6M03N	C≤0.03，Mn≤2.00， Si≤1.00，P≤0.030， S≤0.020，Cr 21.0~23.0, Ni 4.5~6.5,Mo 2.5~3.5, N 0.08~0.20	Annealed, cold rolled	≥450	≥620	≥18	HV≤320
USA	S31803/S32205
JIS	SUS329J3L
German	1.4462

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
* Pressure vessel and high pressure storage tanks, high pressure piping, heat exchangers (chemical process industries).
* Oil and gas pipelines, heat ex-changer pipe.Sewage treatment systems.
* Classifier, bleaching of pulp and paper industry equipment, storage systems.
* Ship or truck cargo box
* Food processing equipment