What Is The Difference Between Austenitic And Martensitic Stainless Steel ?
By producing martensite, martensitic stainless steel is produced. Iron that has been cubically centred and crystallised becomes martensite. The majority of martensitic stainless steels are produced by rapidly cooling austenite after it has been heated. The action is referred to as quenching. The material's quick cooling stops cementite development. Additionally, the procedure stops extra carbon atoms from being expelled and instead artificially retains them inside the material.
The martensitic stainless steels benefit from extremely high abrasion resistance and toughness as a result. The microstructure, where trapped carbon provides great toughness, is in charge of abrasion resistance. Martensitic stainless steels have stronger strength, abrasion resistance, and toughness than their austenitic equivalents, but they exhibit less corrosion resistance. Applications requiring the management of heavy wear and tear, such as platforms, transportation, abrasive surfaces, etc., choose materials with these characteristics. A structure's ability to resist deformation under smaller stresses depends on the material's toughness.
Almost all metallic applications require welding of the steels. The type of material has an impact on the welding needs, welding speed, and welding ease. Compared to martensitic stainless steels, austenitic stainless steels are much simpler to weld. Compared to the majority of their austenitic counterparts, martensitic steels contain more carbon. As a result, the danger of chromium carbide precipitation during welding increases, toughness increases, and corrosion resistance decreases.
Martensitic steels must also be warmed to a specific temperature in order to be properly welded. Although post-weld heat treatments are not necessary for all austenitic stainless steels, they are necessary for martensitic stainless steels in order to harden them and prevent embrittlement. After welding, the martensitic steels' corrosion resistance will drop, whereas austenitic stainless steels continue to be corrosion-resistant.
The 304 austenitic stainless steel is the material type that is most frequently welded. Most austenitic stainless steels have lower carbon levels and chromium values ranging from 16 to 26 percent and up to 22 percent, respectively. This enables them to maintain their corrosion resistance and withstand the welding process. The martensitic grades contain a high carbon content and chromium contents ranging from 12 to 18 percent. To prevent welding cracking, welding must be conducted carefully to restricted joints and extremely thick pieces.
The 400 series of stainless steels contains martensitic steel grades. They range from 0.15 to 0.63 percent carbon by weight. The martensitic stainless steel comes in grades 410, 420, 440A, 420 ultra hone, and 410 Cb. The 200 and 300 series of materials contain austenitic stainless steels. Among the austenitic stainless steels are the nitronic 30, 201, 301, 304, 316, 309, and 316. The martensitic stainless steels are frequently used in cutlery, medical equipment, cookware, stampings for automobiles, staplers, springs, scissors, screwdrivers, industrial blades, pliers, etc. The austenitic stainless steels are utilised in virtually all home, commercial, and architectural settings, as well as in the oil and gas industries.
|EURONORM (EN) STANDARD||EN DESIGNATION||AISI GRADE||C||CR||MO||NI||OTHERS|
|1.4305||X8CrNiS18-9 e||303||< 0.10||18||NS||9||0.3|
|1.4541||X6CrNiTi18-10||321||< 0.08||18||NS||10.5||Ti: 5×C ≤ 0.70|
|1.4571||X6CrNiMoTi17-12-2||316Ti||< 0.08||17.5||2.25||12||Ti: 5×C ≤ 0.70|
|EN Steel designation||European EN||AISI||C||Cr||Mo||Others|
|X4CrNiMo16-5-1||1.4418||-||≤ 0.06||16.0||1.10||Ni: 2.00|
|X5CrNiCuNb16-4||1.4542||630 (17/4PH)||≤ 0.07||16.0||-||Ni: 4.00
Nb: 5xC to 0.45
|EN||MININMUM YIELD STRESS, MPA||TENSILE STRENGTH, MPA||MINIMUM ELONGATION, %||HEAT TREATMENT|
|1.4006||450||650 - 850||15||QT650|
|1.4021||600||650 - 850||12||QT800|
|1.4122||550||750 - 950||12||QT750|
|1.4057||700||900 - 1050||12||QT900|
|1.4418||700||840 - 1100||16||QT900|
|1.4542||790||960 - 1160||12||P960|
|300 Series||301 - 302 - 303 - 304/L - 304H - 316/L - 317L - 317LMN - 321 - 321H - 347 - 347H -309 - 309S - 310 - 310S - 310H - 330|