SS 304L Seamless Pipe - ASTM A312 TP304L Stainless Steel Pipe

Product Description

What It Is and the Standard

SS 304L seamless pipe is austenitic stainless steel pipe in grade TP304L (UNS S30403) to ASTM A312/A312M. This standard covers seamless and welded austenitic stainless steel pipe for high-temperature and general corrosive service. ASME SA-312 is its counterpart in Section II-A of the ASME Boiler and Pressure Vessel Code, and SA-312 is the designation that ASME pressure codes refer to. Seamless pipe has no welding at any stage and is either hot finished or cold drawn. A312 requires solution annealing at 1040 C minimum, followed by rapid cooling. Finishes: solution annealed and pickled, or bright annealed. Passivation is done on request. Marking: ASTM A312 TP304L SMLS.

Grade and Equivalents

304L is the low-carbon version of 304. It resists carbide precipitation, so welds do not need post-weld annealing. For this reason it is used for heavy-gauge welded components (about 5 mm and over). Its corrosion resistance is usually the same as 304. It cannot be hardened by heat treatment and keeps its toughness down to cryogenic temperatures.

• UNS: S30403
• AISI: 304L
• EN: 1.4307 (X2CrNi18-9); 1.4306 (X2CrNi19-11, higher-nickel alternative)
• JIS: SUS304L

Sizes and Dimensions

Dimensions are to ASME B36.19M. The usual range is NPS 1/2 to NPS 24 (21.3 mm to 610 mm OD) in Sch 5S, 10S, 40S and 80S. For example, NPS 3 is 88.9 mm OD, with a wall of 3.05 mm in Sch 10S, 5.49 mm in Sch 40S and 7.62 mm in Sch 80S. A312 also allows other dimensions, so heavier walls such as Sch 160 and XXS are ordered to ASME B36.10M. Under A312, NPS 1/8 to NPS 8 comes in lengths up to 7.3 m (24 ft), with a permissible range of 4.6 to 7.3 m. Cut lengths can be ordered. Ends: plain ends (PE). The size table with OD, wall thickness and kg/m for Sch 10S, 40S and 80S is in the listing images.

Standards and Tests

Tests required by ASTM A312:

• Chemical analysis to A312 Table 1
• Tension test, transverse or longitudinal: 1 per lot of up to 100 pipes, 2 for larger lots
• Flattening test on 5% of pipe from each heat-treated lot
• Hydrostatic test or non-destructive electric test on each pipe

The following are done only when ordered: intergranular corrosion (IGC) test to ASTM A262 Practice E (Supplementary Requirement S7), PMI, ultrasonic testing (UT) and third-party inspection to EN 10204 3.2. In common practice, A312 pipe is supplied with an EN 10204 type 3.1 mill test certificate. That certificate covers only the tests it reports.

Applications and Industries

• Heavy-gauge welded process piping
• Chemical process piping
• Food processing equipment
• Heat exchangers

Industries: food and beverage, chemical and petrochemical, pharmaceutical, and oil and gas.

Supply from Allied Metal & Tubes

Allied Metal & Tubes is based in Khetwadi, Mumbai, Maharashtra. We are stockists and dealers of stainless steel pipes, tubes, sheets and plates, carbon steel seamless pipes, alloy steel pipes and other ferrous and non-ferrous metals. Established in 1993, MSME registered and ISO 9001:2015 certified. We supply all over India. Send us the NPS, schedule, length and quantity you need for a quotation.

FAQ

What is the difference between SS 304 and 304L pipe?
304L has lower carbon (0.035% max), so its welds resist carbide precipitation without post-weld annealing. Its minimum strength is also lower: 485/170 MPa tensile/yield, against 515/205 MPa for 304.

How is SS 304L pipe weight calculated?
kg/m = (OD - WT) x WT x 0.02491, with OD and WT in mm. For NPS 3 Sch 10S (88.9 x 3.05 mm), this gives about 6.52 kg/m.

Can IGC, PMI or UT testing be done?
These are not routine A312 tests. They are done only when ordered, so please mention them in your enquiry.