ASTM vs EN, DIN, JIS and IS: equivalent standards chart

Each standard is written by a different body for its own codes and markets. Two grades can share a nominal 18Cr-8Ni chemistry and still differ in carbon limit, nitrogen allowance, minimum yield strength, test frequency, hydrotest requirement or dimensional tolerance. ASTM A312 TP304 pipe allows 0.08% carbon; EN 1.4301 allows 0.07%. A106 Grade B and EN P265GH are both carbon steel for high-temperature pipe, but their strength minimums and impact requirements are not the same.

So treat this chart as a map for finding the nearest alternative, not as approval to substitute. For pressure parts, the designer or the code decides, and the test certificate must show the material meets the standard actually being certified.

ASTM names the product standard first and the grade second: A312 is stainless pipe, TP316L is the grade within it. The grade alone is identified across North American documents by its UNS number, a letter and five digits, where S marks stainless steel, C copper alloys and K carbon and low-alloy steels; A106 Grade B, for example, is K03006.

European EN standards give every steel a material number and a name. The number, such as 1.4404, is a catalogue reference: 1.4xxx numbers are stainless steels. The name describes the chemistry, which makes it the more useful of the two once you can read it.

JIS names are compact codes. SUS means steel use stainless, followed by the AISI-style number. Pipe and tube grades describe the product and strength: STPT410 is steel tube for piping at high temperature with 410 MPa minimum tensile strength, STPA is the alloy version, and STB is boiler and heat-exchanger tube.

Indian standards follow the ISO-style naming that EN uses, and Indian product standards such as IS 6911 for stainless sheet or IS 2062 for structural steel often sit alongside ASTM on the same project.

For high-alloy steels, including all stainless grades, the name starts with X. The number after it is carbon content in hundredths of a percent, then the main alloying elements with their percentages. X5CrNi18-10 is about 0.05% carbon, 18% chromium and 10% nickel, which is 304. X2CrNiMo17-12-2 is 316L: 0.02% carbon, 17% chromium, 12% nickel, 2% molybdenum.

Low-alloy steels drop the X and use multiplying factors: in 13CrMo4-5, 13 means 0.13% carbon, chromium is 4 ÷ 4 = 1% and molybdenum 5 ÷ 10 = 0.5%. Pressure steels are named by use and strength instead: P265GH is a pressure steel with 265 MPa minimum yield, for elevated temperature.

The first table pairs the pipe and tube specifications we deal in with their nearest counterparts. DIN 17175, 17457 and 17458 have been withdrawn and replaced by EN 10216 and EN 10217, but the old grade names still appear on drawings and nameplates in Indian plants, so they are listed. Rows marked closest are approximate matches.

Copper alloys are easier to cross-reference because the copper and zinc ranges line up closely. The EN numbers below use the CW prefix for wrought products. The IS column gives the Indian standard designation where one is in common use, such as IS 410 for cold-rolled brass sheet and strip.

Grade equivalence is half the story. The product standard sets dimensions, tolerances and testing, and it changes with form even for the same grade.

Dual or triple certification solves many of these problems. Mills often certify stainless pipe to ASTM A312 and ASME SA-312 together, and some to EN 10216-5 as well, so a single heat satisfies several specifications on paper and in fact.

• Carbon limits: a 304 substitute with higher carbon may fail an L-grade requirement after welding
• Strength basis: EN pressure steels are often named by yield, ASTM by tensile, so the numbers do not compare directly
• Impact testing: EN pressure grades may require Charpy tests that the ASTM grade does not, or the reverse
• Dimensions: EN tube sizes are metric and do not always match ASME pipe ODs
• Testing scope: hydrotest, NDT and certificate type differ between standards
• Code acceptance: a boiler or pressure code may accept one standard and not its equivalent

• Start from the standard on the drawing or datasheet, not from the grade name alone
• If you must substitute, compare the actual tables in both standards: chemistry, strength, tests, tolerances
• Get written approval from the designer or client for any substitution on pressure parts
• Ask for dual-certified material where it exists, such as 304/304L or A312 with EN 10216-5
• Check that the test certificate names the standard you are receiving, as covered in our mill test certificate guide

Copper and brass buyers in India rarely use UNS numbers on the phone. They say EC grade, 70/30 or 60/40. Those trade names line up with the formal designations in the chart, but the order and certificate should still name a standard, such as IS 410 CuZn30 or ASTM B36 C26000, so the material can be checked against defined limits rather than a description.

For steam lines in India, the Indian Boiler Regulations list the material specifications they accept, and IBR documentation is needed regardless of which equivalent standard the pipe is made to. Read what an IBR pipe is before substituting any boiler or steam material.