Стандарт ASTM A268/A268M-10(2016)

This guide covers standard specification for a number of grades of nominal-wall-thickness, welded ferritic and martensitic stainless steel tubing for general corrosion-resisting and high-temperature service. The steel shall conform to the required chemical composition for carbon, manganese, phosphorus, sulfur, silicon, nickel, chromium, molybdenum, aluminum, copper, nitrogen, titanium, and columbium. The number of tubes in a lot heat treated by the continuous process shall be determined from the size of the tubes. The steel shall conform to the following tensile properties: tensile strength, yield strength, and elongation. The tubes shall have a hardness number that will not exceed the prescribed Brinell and Rockwell hardness values. Several mechanical tests shall be conducted, namely: tension test; flaring test (for seamless tubes); flange test (for welded tubes); hardness test; reverse flattening test; intergranular corrosion test; and hydrostatic or nondestructive electric test.

Область применения

1.1 This specification2 covers a number of grades of nominal-wall-thickness, stainless steel tubing for general corrosion-resisting and high-temperature service. Most of these grades are commonly known as the “straight-chromium” types and are characterized by being ferromagnetic. Two of these grades, TP410 and UNS S 41500 (Table 1), are amenable to hardening by heat treatment, and the high-chromium, ferritic alloys are sensitive to notch-brittleness on slow cooling to ordinary temperatures. These features should be recognized in the use of these materials. Grade TP439 is used primarily for hot-water tank service and does not require post-weld heat treatment to prevent attack of the heat affected zone.

TABLE 1 Continued
Grade	TP439	. . .	. . .	TP430 Ti	TP XM-27	TP XM-33^A	18Cr-2Mo	29-4	29-4-2	26-3-3	25-4-4	...	. . .	. . .	. . .	. . .	TP468
UNS Designation	S43035	S43932	S41500^B	S43036	S44627	S44626	S44400	S44700	S44800	S44660	S44635	S44735	S32803	S40977	S43940	S42035	S46800
Element	Composition, %
C, max	0.07	0.030	0.05	0.10	0.01^A	0.06	0.025	0.010	0.010	0.030	0.025	0.030	0.015^C	0.03	0.03	0.08	0.030
Mn, max	1.00	1.00	0.5–1.0	1.00	0.40	0.75	1.00	0.30	0.30	1.00	1.00	1.00	0.5	1.50	1.00	1.00	1.00
P, max	0.040	0.040	0.03	0.040	0.02	0.040	0.040	0.025	0.025	0.040	0.040	0.040	0.020	0.040	0.040	0.045	0.040
S, max	0.030	0.030	0.03	0.030	0.02	0.020	0.030	0.020	0.020	0.030	0.030	0.030	0.005	0.015	0.015	0.030	0.030
Si, max	1.00	1.00	0.60	1.00	0.40	0.75	1.00	0.20	0.20	1.00	0.75	1.00	0.50	1.00	1.00	1.00	1.00
Ni	0.50 max	0.50	3.5–5.5	0.75 max	0.5^D max	0.50 max	1.00 max	0.15 max	2.0–2.5	1.0–3.50	3.5–4.5	1.00 max	3.0–4.0	0.30–1.00	. . .	1.0–2.5	0.50
Cr	17.00–	17.0–19.0	11.5–14.0	16.00–	25.0–27.5	25.0–27.0	17.5–19.5	28.0–30.0	28.0–30.0	25.0–28.0	24.5–26.0	28.00–	28.0– 29.0	10.50– 12.50	17.50– 18.50	13.5– 15.5	18.00– 20.00
	19.00			19.50								30.00
Mo	...	...	0.5–1.0	...	0.75–1.50	0.75–1.50	1.75–2.50	3.5–4.2	3.5–4.2	3.0–4.0	3.5–4.5	3.60–4.20	1.8–2.5	. . .	. . .	0.2–1.2	. . .
Al, max	0.15	0.15	. . .	...	...	...	...	...	...	...	...	...	. . .	. . .	. . .	. . .	. . .
Cu, max	...	...	. . .	...	0.2	0.20	...	0.15	0.15	...	...	...	. . .	. . .	. . .	. . .	. . .
N, max	0.04	0.030 (Ti + Cb) {0.20 + 4 (C + N)} min.; 0.75 max	. . .	...	0.015	0.040	0.035	0.020^E	0.020^E	0.040	0.035	0.045	0.020	0.030	. . .	. . .	0.030
Ti	0.20 + 4 (C		. . .	5 × C min;	...	7 × (C + N)	(Ti + Cb)	...	...	(Ti + Cb) =	(Ti + Cb) =	(Ti + Cb) =	. . .	. . .	0.10–0.60	0.30–0.50	0.07–0.30
	+ N) min;			0.75 max		but no less	0.20 + 4			0.20–1.00	0.20 + 4	0.20–1.00
	1.10 max					than 0.20	(C + N)			and 6 ×	(C + N)	and 6 ×
						min; 1.00	min; 0.80			(C + N)	min to	(C+ N)
						max	max			min	0.80 max	min

Cb	...		. . .	...	0.05–0.20	...	...	...	...	...	...	...	0.15– 0.50^F	. . .	(3 × %C + 0.30) min	. . .	0.10–0.60
																	(Ti + Cb) =
																	0.20 +4(C+N)
																	min;0.80 max

(A) For small diameter or thin walls, or both, tubing, where many drawing passes are required, a carbon maximum of 0.015 % is necessary. Small outside diameter tubes are defined as those less than 0.500 in. [12.7 mm] in outside diameter and light wall tubes as those less than 0.049 in. [1.2 mm] in average wall thickness (0.040 in. [1 mm] in minimum wall thickness).

(B) Plate version of CA6NM.

(D) Nickel plus copper.

(E) Carbon plus nitrogen = 0.025 % max.

(F) Cb/(C + N) = 12 min.

1.2 An optional supplementary requirement is provided, and when desired, shall be so stated in the order.

1.3 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. The inch-pound units shall apply unless the “M” designation of this specification is specified in the order.

Ключевые слова:

ferritic stainless steel; seamless steel tube; stainless steel tube; steel tube; welded steel tube;

Взамен:

ASTM A268/A268M-10

Заменен на:

ASTM A268/A268M-20

Ссылочные документы:

ASTM E213ASTM A1016/A1016MASTM A763ASTM A480/A480MASTM E273

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