Chemical composition of martensitic and precipitation hardening stainless steels (melt analysis)

Martensitic and Precipitation Hardening Stainless Steel Chemical Composition (Melt Analysis)

Stainless steels are metals with high resistance to corrosion, strength, and malleability. Different classes of stainless steels are available, each with specific chemical composition and mechanical properties. This article looks at the composition and characteristics of two types of stainless steel - martensitic and precipitation hardening stainless steels.

Martensitic stainless steel is a type of stainless steel that is formed when a lower alloy temperature is heated until it reaches a martensite-type crystalline structure. This type of stainless steel has very high strength and hardness but low ductility and formability due to its low chromium content. Martensitic stainless steel is typically used in construction applications, such as bridges. The chemical composition of martensitic stainless steel makes it resistant to oxidation, although it does not provide the corrosion resistance of austenitic stainless steel or other steels with higher chromium content.

Precipitation hardening stainless steel is a type of stainless steel that is similar to martensite but with a higher chromium content. It is formed when a high alloy temperature is heated until a secondary hardening phase forms. This type of stainless steel has excellent strength, hardness and corrosion resistance compared to martensitic stainless steel. Thanks to its high chromium content, precipitation hardening stainless steel is suitable for a wide range of applications, including medical and aerospace applications.

To analyze the chemical composition of martensitic and precipitation hardening stainless steel, a melt analysis test can be used. In this type of test, a sample of the alloy is melted and then analyzed using spectroscopy. This information can then be used to determine the chemical composition and relative abundances of the various elements present in the material, such as carbon, chromium, nickel, molybdenum, and manganese. The results of the melt analysis test can then be used to determine the suitability of the material for a particular application.

In general, martensitic stainless steel contains less than 16 percent chromium, with the remainder of its composition dominated by iron (Fe). Precipitation hardening stainless steel usually contains between 16 and 18 percent chromium, with the remainder being iron (Fe). The amounts of molybdenum and nickel also vary, with martensitic stainless steel typically containing less than 0.25 percent of each and precipitation hardening stainless steel typically containing between 0.35 to 2.00 percent of each.

In summary, martensitic and precipitation hardening stainless steels are two types of stainless steel with very different properties. Martensitic stainless steel is typically used for construction projects due to its high strength and hardness, although it does not provide excellent corrosion resistance or formability. Precipitation hardening stainless steel has excellent corrosion resistance, formability, and strength due to its higher chromium content. To analyze the chemical composition of these two types of stainless steel, melt analysis tests can be used.

The chemical composition of martensitic and precipitation hardening stainless steel is important for determining its properties. The analysis below is based on averages of multiple tests.

Martensitic stainless steel is made up of iron (Fe) with a range of 11-14%, chromium (Cr) ranging from 16-18%, and carbon (C) ranging from 0.08-1.2%. Manganese (Mn) is present in a range of 1-2.5%, while silicon (Si) is present in a range of 0.1-1%. Phosphorus (P) and sulphur (S) are present in much lower levels, typically in the order of 0.025% or less.

Precipitation hardening stainless steel has high levels of nickel (Ni) and low levels of carbon, compared to martensitic steel. On average, precipitation hardening stainless steel contains 15-19% Cr, 0.03-0.08% C, 0.5-1.2% Mn, 2-2.5% Ni, and 6-8% Mo. Silicon levels are similar to martensitic stainless steel, while phosphorus and sulphur levels are significantly lower, usually in the order of 0.005-0.03%.

These compositions result in differences in mechanical properties and how the steel behaves under certain conditions. Martensitic stainless steel is harder, but less ductile, than precipitation hardened steel. It is also less resistant to corrosion. Precipitation hardened steel has a higher strength, but is more expensive to produce because of the high nickel content.

In conclusion, the chemical composition of martensitic and precipitation hardening stainless steel differs in terms of the amounts of carbon, chromium, manganese, nickel, and other elements present. These differences dictate the mechanical properties and corrosion resistance of the steel.