ASTM A312 Stainless Steel Pipe Specifications

1. Scope

1.1 This standard is applicable to austenitic seamless and longitudinally welded steel pipes for high-temperature operation and general corrosive operation.

Note 1: When the low-temperature impact test index is required to reach the absorbed energy of 15 feet per pound (20 joules) or the lateral expansion of 15 mils, some austenitic stainless steel pipes in this standard have been accepted by the relevant pressure vessel or pipeline specifications, and the actual impact test is not required. For example, the grades 304304L and 347 have been recognized by the ASME Pressure Vessel Code and ANSI B31.3 Chemical Equipment and Oil Refining Equipment Piping Code. When used at low temperature – 425F (- 250C), it is not necessary to pass the impact test for identification. Other AISI stainless steel grades generally allow no impact test when used at temperatures as low as – 325F (- 200C). In some cases, impact test may be required. For example, steel pipes with chromium or nickel content exceeding AISI range and carbon content exceeding 0. When 10% of steel pipes are to be used at temperatures lower than – 50F (- 46C), impact tests shall be conducted according to the provisions of Section I of ASME standards.

1.2 The grades TP304H, TP309H, TP309HCb, TP310H, TP310HCb, TP310H, TP310HCb, TP316H, TP321H, TP347H and TP348H are the improved grades of TP304, TP309Cb, TP309S, TP310Cb, TP310S, TP316, TP321, TP347 and TP348, which are intended to be used in high-temperature industry

1.3 This standard specifies selective supplementary requirements for steel pipes requiring more tests These supplementary requirements propose some additional tests. If necessary, one or more of them can be specified in the order

1.4 In the attached table of this standard, the sizes of stainless steel seamless steel pipe, welded steel pipe and welded steel pipe are listed according to ANSI B36.19 standard. Steel pipes of other sizes can be supplied as long as they meet all requirements of this standard

1.5 Values expressed in inch-pound units and SI (metric) units are regarded as standard values respectively The units in the text and table are indicated by brackets. The values indicated by each unit system are not exact equivalent values. Therefore, each unit system must be used separately. If the values of the two unit systems are mixed, they will not conform to ASTM standards If the standard number with M is not specified in the order, it shall be supplied in inch-pound units

Note 2: In this standard, the code NPS (nominal size of steel pipe) without size specification has replaced traditional terms such as “nominal diameter”, “size” and “nominal size”

2. Applicable documents

2.1 ASTM standards:

A262 Test Method for Susceptibility to Intergranular Corrosion of Austenitic Stainless Steel

A370 Methods and definitions for mechanical property test of steel

A530/A530M Special Carbon and Alloy Steel Pipe General Requirements]

E112 Determination method of average grain size

E381 Method for Macroetch Test, Inspection and Rating of Steel (including Bar, Billet, Billet and Forged Steel)

E527 Recommended Practice for Metal and Alloy Numbering (UNS)

2.2 ANSI standards:

B1.20.1 Steel pipe threads for general purposes

B36.10 Welded and seamless malleable steel pipe

B36.19 Stainless steel pipe

2.3 AWS standards

A5.9 General requirements for corrosion-resistant chromium and chromium-nickel steel welding wires and rods

3.1 The steel pipes supplied according to this standard shall meet the applicable requirements of the current edition of ASTM A450/A450M standard, unless otherwise specified

4. Supply content

4.1 The order for steel pipes ordered according to this standard shall include the following contents as required, and the steel pipes required shall be properly described with stems:

4.1.1 Quantity (feet, meters or pieces)

4.1.2 Steel pipe name (austenitic steel pipe)

4.1.3 Process (seamless or welded)

4.1.4 Brand (Table 1)

4.1.5 Size (NPS or outer diameter and serial number or average)

4.1.6 Length (fixed or unfixed) Section 10

4.1.7 End processing (the end section of ASTM A530/A530M standard)

4.1.8 Optional requirements (Section 7)

4.1.9 Required test report (section of ASTM A530/A530M standard on certificate of conformity)

4.1.10 ASTM standard number

4.1.11 Special requirements or any selected supplementary requirements, or both.

5. Material manufacturing process

5.1 Manufacturing process

5.1.1 Steel pipes shall be manufactured by seamless production process or automatic welding process without filler metal during welding

5.1.2 Welded steel pipes equal to and smaller than NPS 14 shall have one longitudinal weld Steel pipes larger than NPS 14 can be produced by forming and welding two longitudinally welded pipe strips with the consent of the Demander Each weld shall be tested, inspected, inspected or processed

5.1.3 According to the choice of the manufacturer, steel pipes can be supplied by hot processing or cold processing

5.1.4 The steel pipe shall be free of scale and foreign iron particles All steel pipes that have been bright annealed do not need pickling, shot blasting or surface finishing The demander may require passivation treatment

5.2 Heat treatment

5.2.1 All steel pipes shall be delivered in heat treatment state Except for the steel pipes of H grade, S30815, S31272 and S31254, the heat treatment method is to heat the steel pipes to not less than 1900F (1040C), and then quench them in water or quench them by other methods

5.2.2 All H twisted steel pipes shall be delivered in solution heat treatment state If there is flash processing during the manufacturing process, the minimum solution treatment temperature of steel pipes of grades TP321H, TP347H and TP348H shall be 2000 ° F (1100 ° C), while that of steel pipes of grades TP304H and TP316H shall be 1900 ° F (1040 ° C) If steel pipes of grade H are hot-rolled, the minimum solution treatment temperature of steel pipes of grades TP321H, TP347H and TP348H shall be 1925 ° F (1050 ° C) The steel pipes of TP304H and TP316H are 1900 ° F (1040 ° C) The minimum solution treatment temperature of S30815 and S31272 steel pipes shall be 1900 ° F (1040 ° C)

5.2.3 The heat treatment method of S31254 steel pipe shall be to heat the steel pipe to a temperature not lower than 2100F (1150C), and then quenched in water or quenched by other methods

5.3 If the solution treatment temperature of steel pipes with the grades of TP309HCb, TP310HCb, TP321, TP321H, TP347, TP347H, TP348 and TP348H is higher than 1950C, their intergranular corrosion resistance may be damaged when they are exposed to the sensitized state in the future. If the demander has provisions, low-temperature stabilization treatment or solution annealing shall be carried out after the initial high-temperature solution annealing (see Supplementary Requirement S6)

5.4 Grain size

5.4.1 The grain size of steel pipes of grades TP309, TP309HCb, TP310H and TP310HCb shall be 6 or coarser when measured according to the test method of ASTM E112

6. Chemical composition

6.1 The chemical composition of steel shall meet the requirements specified in Table 1

7. Finished product analysis

7.1 When required by the Demander, the manufacturer shall take one welded pipe blank or flat rolled material from each furnace of steel, or two from a batch of steel pipes for analysis. A batch of steel pipes shall consist of the following steel pipes of the same size and wall thickness produced by the same furnace of steel:

NPS number of steel pipes in a batch

Less than 2400 pieces or the rest

2-5 200 pieces or the rest

5 and more than 5 100 pieces or the rest

7.2 The analysis results shall be reported to the Demander or the Demander’s representative and shall comply with the provisions of Section 6

7.3 During the analysis of finished products specified in Article 7.1, if one of the analysis results does not meet the requirements specified in Section 6, the furnace or batch of each tube blank or steel pipe can be analyzed, and all qualified tube blanks or steel pipes shall be accepted

8. Tensile property requirements

8.1 The tensile properties of steel pipes shall meet the requirements specified in Table 2

9. Mechanical property test and grain size determination required

9.1 Transverse and longitudinal tensile test – take one sample from a batch of no more than 100 steel pipes for one tensile test Take two steel pipes from a batch of more than 100 steel pipes for tensile test

Note 3: For mechanical property test, “batch” refers to all steel pipes with the same nominal size and wall thickness (or serial number) produced from the same furnace steel and subjected to the same final heat treatment in the following two furnaces: (1) heat treatment in a continuous furnace or (2) heat treatment in a batch furnace (batch furnace is equipped with a self-recording pyrometer, and the temperature is automatically controlled within the range of 50F (30C)) A batch refers to (a) every 200 feet (60 meters) or the rest of it, or (b) the same batch of steel pipes for furnace heat treatment

9.2 Flattening test – For steel pipes heat treated in batches or furnaces, 5% of the steel pipes shall be taken from each heat treatment batch for flattening test. For steel pipes heat treated in continuous furnaces, 5% of the steel pipes in a sufficient batch shall be taken for testing, but at least not less than two

9.2.1 For welded steel pipes, the bending test of the transverse guide surface of the weld can be carried out in accordance with the method described in the appendix of ASTMA370 standard on steel pipe production to replace the flattening test. If the ductility of the weld after bending is considered to be qualified. The test sample shall be taken from 5% of the batch of steel pipes, or from the test steel plate with the same material as the steel pipe. The test steel plate is placed at the end of the cylinder and welded on it, As the extension of longitudinal weld of steel pipe

9.3 Hydrostatic test – If there is no special exemption in Article 9.4, each finished steel pipe shall be subjected to hydraulic test in accordance with ASTM A530/A530M

9.4 When the size of the steel pipe is equal to or equal to NPS10, the Demander may waive the requirements of the hydraulic test after negotiation with the manufacturer, and the Demander shall carry out a system test to replace the hydraulic test. Each steel pipe not supplied through the hydraulic test of the manufacturer shall be marked with “NH”

9.5 Grain size – steel pipes of grades TP309H, TP309HCb, TP310H, TP310HCb, and UNS S32615. The grain size shall be measured on the same number of steel pipes as the flattening test

10. Length

10.1 The length of the steel pipe shall conform to the following conventions:

10.1.1 Unless otherwise agreed, all sizes of steel pipes from NPS 1/8 to NPS 8 can be supplied up to 24 feet in length (Note 4). The steel pipe with shorter length can also be delivered, but its quantity and minimum length shall be determined by the manufacturer and the demander.

Note 4: This value is used when ordering based on the English unit symbol of this standard. When the “M” (metric) unit symbol in this standard is used as the ordering basis, the corresponding metric value shall be agreed between the manufacturer and the demander.

10.1.2 If cut to length is required, the required size shall be indicated in the order. The length of steel pipe shall not be shorter than the specified length, nor more than 1/4 inch (6 mm)

10.1.3 Unless otherwise specified, steel pipes are not allowed to have connecting pipes.

11. Machining accuracy, surface quality and appearance

11.1 Finished steel pipes shall have reasonable straightness and good processing quality. Defects can be removed by research methods, but the wall thickness of steel pipe shall not be reduced to less than the thickness specified in Section 7 of ASTM A530/A530M standard.

12. Weld repair

12.1 For steel pipes with diameter equal to or greater than NPS 6 and nominal wall thickness equal to or greater than 0.200 inch, the weld can be repaired with filler metal using the same welding method specified in the section of ASTM A530/A530M on welding repair for steel defects

12.2 The weld repair length of the weld shall not exceed 20% of the weld length

12.3 Only gas shielded tungsten arc welding shall be used for welding repair, and AWS A5 shall be used at the same time. 9 Bare electrode of the same grade as the repaired stainless steel pipe specified in the latest version. (See Table 3)

12.4 Steel pipes repaired with filler metal shall be marked with uniform marks, and the same marks and instructions shall also be provided in the test certificate

13. Finished product mark

13.1 In addition to the marks specified in ASTM A530/A530M standard, the manufacturer’s own marks shall also be marked (such as the NH mark in Article 9.4. For steel pipes with grades TP304H, TP316H, TP321H, TP347H, TP348H and S30815, the heat number and heat treatment batch number shall also be included in the marks. If specified in the order, the weight of steel pipes larger than NP54 shall also be marked

Supplementary requirements for steel pipes requiring special consideration

One or more of the following supplementary requirements shall be implemented only when explicitly put forward in the order. The Demander can specify different times of test and analysis than those specified in the supplementary requirements. The provisions of re-inspection and re-processing in the supplementary requirements can also be modified when agreed by the Demander and the manufacturer

S1 Finished product analysis

S1.1 For steel pipes equal to or greater than NPS 5, a representative sample and a finished product analysis shall be taken from every 10 steel pipes or one steel pipe from the rest of each furnace

S1.2 For steel pipes less than NPS 5, 10 steel pipes shall be taken from each heat of steel or 10% of steel pipes from each heat of steel (whichever is smaller) shall be taken for finished product analysis

S1.3 A single steel pipe with chemical composition that does not conform to the provisions of Section 6 shall be pre-rejected

S2. Transverse tensile test

S2.1 Take 10% of steel pipes from each furnace and conduct a transverse tensile test at one end This only applies to steel pipes equal to and larger than NPS 8

S2.2 If the sample of any steel pipe does not meet the specified tensile property requirements, the steel pipe shall be rejected

S3. Flattening test

S3.1 Specimens shall be cut from one end or both ends of each steel pipe for flattening test specified in ASTM A530/A530M standard. The test can also be conducted with steel pipe cutting head If this supplementary requirement is specified, the number of tests for each steel pipe shall also be specified in advance. Before the first step of flattening test is successfully completed for any steel pipe, if the steel pipe is unqualified due to lack of toughness, the steel pipe shall be pre-picked out according to ASTM.

TABLE 1  Chemical Requirements

Grade	UNS	C	Mn	P	S	Si	Ni	Cr	Mo	Ti	Colum	Ta	N
Designation	Max	Max	Max	Max	Max	Max	Blum plus ta
TP304	S30400	0.08	2	0.04	0.03	0.75	8.00-11.0	18.0-20.0
TP304H	S30409	0.04-0.10	2	0.04	0.03	0.75	8.00-11.0	18.0-20.0
TP304L	S30403	0.035	2	0.04	0.03	0.75	8.00-13.0	18.0-20.0
TP304N	S30451	0.08	2	0.04	0.03	0.75	8.00-11.0	18.0-20.0				0.10-0.16
TP304LN	S30453	0.035	2	0.04	0.03	0.75	8.00-11.0	18.0-20.0				0.10-0.16
TP309Cb	S30940	0.08	2	0.045	0.03	0.75	12.0-16.0	22.0-24.0	0.75		10xC
											min
											1.1
											max
TP309H	S30909	0.04-0.10	2	0.04	0.03	0.75	12.0-15.0	22.0-24.0
TP309HCb	S30941	0.04-0.10	2	0.045	0.03	0.75	12.0-16.0	22.0-24.0	0.75		10xC
											min
											1.1
											max
TP309S	S30908	0.08	2	0.045	0.03	0.75	12.0-15.0	24.0-26.0	0.75
TP310Cb	S31040	0.08	2	0.045	0.03	0.75	19.0-22.0	24.0-26.0	0.75		10xC
											min
											1.1
											max
TP310H	S31009	0.04-0.10	2	0.04	0.03	0.75	19.0-22.0	24.0-26.0
TP310HCb	S31041	0.04-0.10	2	0.045	0.03	0.75	19.0-22.0	24.0-26.0	0.75
TP310S	S31008	0.08	2	0.045	0.03	0.75	19.0-22.0	24.0-26.0	0.75
	S31272	0.08-0.12	1.5-2.00	0.03	0.015	0.3-0.7	14.0-16.0	14.0-16.0	1.0-1.4	0.3-0.6
			2			0.75
TP316	S31600	0.08	2	0.04	0.03	0.75	11.0-14.0	16.0-18.0	2.0-3.0
TP316H	S31609	0.04-0.10	2	0.04	0.03	0.75	11.0-14.0	16.0-18.0	2.0-3.0
TP316L	S31603	0.035	2	0.04	0.03	0.75	10.0-15.0	16.0-18.0	2.0-3.0
TP316N	S31651	0.08	2	0.04	0.03	0.75	11.0-14.0	16.0-18.0	2.0-3.0			0.10-0.16
TP316LN	S31653	0.035	2	0.04	0.03	0.75	11.0-14.0	16.0-18.0	2.0-3.0			0.10-0.16
TP317	S31700	0.08	2	0.04	0.03	0.75	11.0-14.0	18.0-20.0	3.0-4.0
TP317L	S31703	0.035	2	0.04	0.03	0.75	11.0-15.0	18.0-20.0	3.0-4.0
TP321	S32100	0.08	2	0.04	0.03	0.75	9.00-13.0	17.0-20.0
TP321H	S32109	0.04-0.10	2	0.04	0.03	0.75	9.00-13.0	17.0-20.0
TP347	S34700	0.08	2	0.04	0.03	0.75	9.00-13.0	17.0-20.0
TP347H	S34709	0.04-0.10	2	0.04	0.03	0.75	9.00-13.0	17.0-20.0
TP347LN	S34751	0.005-0.02	2	0.04	0.03	0.75	9.00-13.0	17.0-20.0			0.2-0.5	0.06-0.10
TP348	S34800	0.08		0.04	0.03		9.00-13.0	17.0-20.0

• a. New designation established in accordance with Practice E 527 and SAE J1086.

• b. Maximum, unless othervise indicated.

• c. The method of analysis for nitrogen shall be a matter of agreement between the purchaser and manufacturer.

• d. For welded TP316, TP316N, TP316LN, AND TP316H pipe, the nickel range shall be 10.0-14.0

• e. For small diameter or thin walls or both, where many drawing passes are reqired, a carbon maximum of 0.040% is necessary
•   in grades TP304L AND TP316L. Small out diameter tubes are defined as those less than 0.500in.[12.7mm] in
•   outside diameter and light wall tubes as those less than 0.049in.[1.20mm] in average wall thickness (0.041[1.10mm] in     
•   minimum wall thickness)
• f. The titanium content shall be not less than five times the carbon content and not more than 0.7%.
• g. The titanium content shall not less than four times the carbon content and not more than 0.60%
• h.The columbium plus tantalum content shall be not less than ten times the carbon content and not more than 1.00%
• I. The columbium plus tantalum content shall be not less than eight times the carbon content and not more than 1.0%
• j. For welded pipe, the phosphorus maximum shall be 0.045%
• k. Grade S34751 shall have a columbium (niobium) plus tantalum content of not less than 15 times the carbon content.

TABLE 2  Annealing Requirements

Grade or UNS Designation	Solution Treating Temperature	Cooling Requirements
All grades not individually listed below:	1900F°[1040°C]	Rapid
	2000°F[1100°C]
TP321H, TP347H, TP348H	1925°F[1050°C]
Cold Rolled	1900°F[1040°C]
Hot Rolled Only	1900°F[1040°C]
TP304H, TP316H	1900°F[1040°C]
Cold, Rolled	1900°F[1040°C]
Hot Rolled Only
TP309H,TP309HCb,TP310H,	1920°F[1050°C]
TP310HCb	1920F[1050C]	Rapid
S30815	2100°F[1150°C]	Rapid
S31272	2050-2140°F[1120-1170°C]	Rapid
S31254	Rapid
S24565	2010°F[1100°C]	Rapid
S35315	2025°F[1110°C]	Rapid
N08367	2000F[1100C]	Rapid
N08904

• A. New designation established in accordance with Practice E 527 and SAEJ 1086
• B. Minimum, unless otherwise stated.
• C Rapid: Pipe shall be water quenched or rapidly cooled by other means.

TABLE 3  Tensile Requirements

Grade	UNS	Tensile	Yield  Strength, min
Designation	Strength, min	Ksi[Mpa]
TP304L	S30403	70[485]	25[170]
TP316L	S31603	70[485]	25[170]
TP304	S30400	75[515]	30[205]
TP304H	S30409	75[515]	30[205]
TP309Cb	S30940	75[515]	30[205]
TP309H	S30909	75[515]	30[205]
TP309HCb	S30941	75[515]	30[205]
TP309S	S30908	75[515]	30[205]
TP310Cb	S31040	75[515]	30[205]
TP310H	S31009	75[515]	30[205]
TP310HCb	S31041	75[515]	30[205]
TP310S	S31008	75[515]	30[205]
	S31272	65[450]	29[200]
TP316	S31600	75[515]	30[205]
TP316H	S31609	75[515]	30[205]
TP317	S31700	75[515]	30[205]
TP317L	S31703	75[515]	30[205]
TP321	S32100
Welded		75[515]	30[205]
Seamless
<3/8in.		75[515]	30[205]
>3/8in.		70[485]	25[170]
TP321H	S32109
Welded		75[515]	30[205]
Seamless
<3/8in.		75[515]	30[205]
>3/8in.		70[485]	25[170]
TP347	S34700	75[515]	30[205]
TP347H	S34709	75[515]	30[205]
TP347LN	S34751	75[515]	30[205]
TP348	S34800	75[515]	30[205]
Elongation in 2 in. or 50mm(or 4D), min,%	Longitudinal	Transverse
All Grades except S31050 and S32615	35	25
S32615, S31050	25
N08367	30

TABLE X1.1Continued

NPS	Out Diameter	Schedule 5SA	Schedul 10SA	Schedule 40S	Schedule 80S
Designator	In.     mm	In.   mm	In    mm	In    mm	In    mm
1/4”	0.540   13.72		0.065  1.65	0.088  2.24	0.119  3.02
3/8”	0.675   17.15		0.065  1.65	0.091  2.31	0.126  3.20
1/2”	0.840   21.34	0.065 1.65	0.083  2.11	0.109  2.77	0.147  3.73
3/4”	1.050   26.67	0.065 1.65	0.083  2.11	0.113  2.87	0.154  3.91
1”	1.315   33.40	0.065 1.65	0.109  2.77	0.133  2.38	0.179  4.55
1 1/4″	1.660   42.16	0.065 1.65	0.109  2.77	0.140  3.56	0.191  4.85
1 1/2″	1.900   48.26	0.065 1.65	0.109  2.77	0.145  3.68	0.200  5.08
2″	2.375   60.33	0.065 1.65	0.109  2.77	0.154  3.91	0.218  5.54
2 1/2″	2.875   73.03	0.083 2.11	0.120  3.05	0.203  5.16	0.276  7.01
3″	3.500   88.90	0.083 2.11	0.120  3.05	0.216  5.49	0.300  7.62
3 1/2″	4.000  101.60	0.083 2.11	0.120  3.05	0.226  5.74	0.318  8.08
4″	4.500  114.30	0.083 2.11	0.120  3.05	0.237  6.02	0.337  8.56
5″	5.563  141.30	0.109 2.77	0.134  3.40	0.258  6.55	0.375  9.52
6″	6.625  168.28	0.109 2.77	0.134  3.40	0.280  7.11	0.432  10.97
8″	8.625  219.08	0.109 2.77	0.148  3.76	0.322  8.18	0.500  12.70
10″	10.750 273.05	0.134 3.40	0.165  4.19	0.365  9.27	0.500  12.70
12″	12.750 323.85	0.156 3.96	0.180  4.57	0.375  9.52	0.500  12.70
14″	14.000 355.60	0.156 3.96	0.188  4.78
16″	16.000 406.40	0.165 4.19	0.188  4.78
18″	18.000 457.20	0.165 4.19	0.188  4.78
20″	20.000 508.00	0.188 4.78	0.218  5.54
22″	22.000 558.80	0.188 4.78	0.218  5.54
24″	24.000 609.60	0.218 5.54	0.250  6.35
30″	30.000 762.00	0.250 6.35	0.312  7.92