Stainless Steel Grades

There are 150 plus stainless steel grades have been discovreed and expanded to use in various applications, each grade exhibits unique chemical composition澳门凯发娱乐 and mechanical property, knowing characteristics of these grades is necessary lesson to select a right grade to your use.

There are so many stainless steel grades, and equivalents defined by different organizations, it is hard to say which one is the best, just the most suitable grade depends on properties and applications.

Five Types of Stainless Steel

There are five types of stainless steel depending on their metallurgical micros­truc­ture, each group possesses special alloying elements and composition that will affect stainless steel properties and uses.

  1. Austenitic stainless steels
  2. Martensitic stainless steels
  3. Ferritic stainless steels
  4. Duplex (ferritic-austenitic) stainless steels
  5. Precipitation-Hardening (PH) stainless steels

Austenitic Stainless Steel

These grades are the most widely used stainless stee due to their excellent properties to resist corrosion, Austenitic Stainless Steel grades contain high Chromium and Nickel content, they cannot be hardened through heat treatment, but can be hardened through cold-working, the most common austenitic alloys are iron-chromium-nickel steels and are widely known as the 300 series providing fine mechanical properties

Typical grades are given as following:

  • 304, standard 18/8 grade, the most commonly used stainless steel grade
  • 316, contains 16% to 18% chromium and 11% to 14% nickel. It also has molybdenum added to the nickel and chrome of the 304.
  • 316L, it is low carbon of 316 grade, addition of molybdenum alloy improve corrosion resistance, particular in chloride environments
  • 321, Titanium addition of at least five times the carbon content, lower risk of weld decay
  • 904L, high Chromium content increase general corrosion, pitting and stress corrosion cracking resistance

Martensitic stainless steels

This group contains 10。5% minimum Chromium, and without nickel, Martensitic Stainless Steels also have a moderate resistance to corrosion but again this resistance isn’t as strong as the Austenitic stainless steels, they can be harden by heat treated, grades are mainly used where hardness, strength, are required。

  • 410, standard martensitic grade for slight corrosion applications
  • 416, good machinability
  • 420, Higher hardness martensitic grade, contains increased carbon to improve mechanical properties.
  • 431, best corrosion resistance properties of all the martensitic grades. It has excellent tensile and torque strength, and good toughness

Ferritic stainless steels

These grades contain Chromium alloy with the absence of Nickel, moderate corrosion resistance, they cannot be hardened using heat treatment, cost saving grades, but not as good for welding.

  • 409, decreased chromium content, Automotive exhaust grade
  • 430, A basic Ferritic grade, used for mildly corrosive environments, ike nitric acid, sulfur gases, and many organic and food acids
  • 436, columbium added for corrosion and heat resistance
  • 446, higher chromium content improve corrosion and scaling resistance at high temperatures

Duplex (ferritic-austenitic) stainless steels

Duplex grades are a combination of austenitic and ferritic material, having very high strength, and better toughness and ductility than the ferritic grades.

  • 2205, the most widely used duplex grade, high resistance to pitting and stress corrosion
  • 2507, super duplex grade, the high chromium, molybdenum, and nitrogen levels provide excellent resistance to pitting, crevice, and general corrosion.

Stainless steel grades can be also grouped into

  • 200 Series
  • 300 Series
  • 400 Series
  • 500 Series
  • 600 Series

Stainless Steel Grades and Equivalents

There are several stainless steel grade systems in the world, each standard has unique No. or name, in many cases, these grades can be equivalent, due to their the same or similar chemical composition and properties.

  • ASTM, American Society for Testing and Materials
  • EN, European Standard
  • DIN, German Standard
  • JIS, Japanese Industrial Standards
  • GB, Chinese Standard
  • BS, British Standards
EN DesignationAlternative Designations
Steel nameSteel numberAISIUNSGBBSGeneric/Brand
Ferritic stainless steels
X2CrNi121.4003S409773CR12
X2CrTi121.4512409S40900409S19
X6CrAl131.4002405S40500405S17
X6Cr171.4016430S43000430S17
X3CrTi171.4510439S43035
X2CrMoTi18-21.4521444S44400
X6CrMoNb17-11.4526436S43600
X2CrTiNb181.4509441S4393218CrCb
Austenitic stainless steels
X2CrNiN18-71.4318301LNS30153
X2CrNi18-91.4307304LS30403022Cr19Ni10304S11
X2CrNi19-111.4306304LS30403
X2CrNiN18-101.4311304LNS30453304S51
X5CrNi18-101.4301304S3040006Cr19Ni10304S15
X6CrNiTi18-101.4541321S3210006Cr18Ni11Ti321S31
X6CrNiNb18-101.4550347S3470006Cr18Ni11Nb347S31
X2CrNiMo17-12-21.4404316LS31603022Cr17Ni12Mo2316S11
X5CrNiMo17-12-21.4401316S3160006Cr17Ni12Mo2316S31
X6CrNiMoTi17-12-21.4571316TiS3163506Cr17Ni12Mo2Ti320S31
X2CrNiMo17-12-31.4432316LS31603316S13
X2CrNiMoN17-3-31.4429316LNS31653
X3CrNiMo17-13-31.4436316S31600316S33
X2CrNiMo18-14-31.4435316LS31603316S13
X2CrNiMoN17-13-51.4439317LMNS31726
X1NiCrMoCu25-20-51.4539N08904015Cr21Ni26Mo5Cu2904S13904L
X1CrNiMoCuN20-18-71.4547S31254015Cr20Ni18Mo6CuN254SMO
X6CrNiMoNb17-12-21.4580S31640
X2CrNiMo18-15-41.4438317LS31703022Cr19Ni13Mo3317S12
X1CrNiMoCuN24-22-81.4652S32654654SMO
X1NiCrMo31-27-41.4563N08028Sanicro 28
X1CrNiMoCuN25-25-51.4537N08932
X1CrNiMoCuNW24-22-61.4659S31266
X1NiCrMoCuN25-20-71.4529N089251925hMo
Austenitic stainless steels – heat resisting Grades
X15CrNiSi20-121.4828
X9CrNiSiNCe21-11-21.4835S30815253 MA
X12CrNi23-131.4833309S30900309S24
X8CrNi25-211.4845310SS3100006Cr25Ni20310S24
X6CrNiSiNCe19-101.4818S30415153 MA
X6NiCrSiNCe35-251.4854S35315353MA
X10NiCrSi35-191.4886N08330330
Austenitic-ferritic stainless steels
X2CrMnNiN21-5-11.4162S321012101 LDX
X2CrNiN23-41.4362S323042304
X2CrNiMoN12-5-31.4462S31803/S32205022Cr23Ni5Mo3N2205
X2CrNiMoN25-7-41.44102507
X2CrNiMoCuEWN25-7-41.4501S32760Zeron 100