Category: Elevated & Low Temperature Properties
BS EN 10269 is the material standard for stainless and heat-resisting steels, a selection of low alloy steels and some nickel alloys for fasteners. The elevated and sub-zero temperature mechanical properties shown in this article include 0.2% proof, tensile and impact (charpy) strengths.
BS EN 10272 is the material standard for stainless steel bars for pressure purposes. The elevated and sub-zero temperature mechanical properties shown in this article include 0.2% proof, tensile and impact (charpy) strengths. Generally, the grades included have the same chemical compositions as bar grades specified in BS EN 10088-3, which also tabulates their ambient temperature mechanical properties. The exception is grade 1.4951 which was added in the 2007 edition of the spec. Recommended annealing heat treatment temperatures for the steels covered are also tabulated.
PLEASE NOTE THAT PREVIOUS VERSIONS OF THIS ARTICLE HAD A SIGNIFICANT ERROR IN THE VALUES SHOWN FOR PROOF STRENGTHS OF DUPLEX STAINLESS STEELS. THE PRESENT ARTICLE HAS BEEN THOROUGHLY REVISED TO REFLECT THE VALUES GIVEN IN THE STANDARD. Design tensile stress values at temperatures up to 550°C are tabulated for all ferritic, martensitic and duplex types covered in the BS EN 10028-7 standard. Space limits the range of austenitic grades that can be conveniently displayed and so only a selection of some of the more 'common' the austenitic grade properties are included. Recommended annealing heat treatment temperatures for the steels covered are also tabulated.
Youngs modulus and thermal expansion data is tabulated for a range of commonly used grades shown in BS EN 10088-1. More detailed 'typical' data follows for austenitic steel types only from the INCO publication 'Austenitic chromium-nickel stainless steels-engineering properties at elevated temperatures', including tensile and shear modulus data, Poisson's ratio, density, thermal expansion, conductivity, specific heat and electrical resistivity.
Stainless steels do not have an intrinsic 'fire rating'. Tests to assess fire resistance are performed on specific fabrications under precise conditions to BS476 parts 20, 21 (load-bearing elements) and 22 (non-load-bearing elements). Fire tests results on some specific products demonstrate the good fire resisting properties of stainless steels in building and ship bulkhead applications. (186)
Stainless steels are widely used for their good oxidation resistance at elevated temperatures. Although other forms of attack, such as sulphidation and carburisation need to be considered in certain applications, oxidation is of primary importance. Oxidation resistance is dependent, primarily, on the chromium content of the steel. The strength of the steel at the intended service temperature is also important when selecting stainless steels for high temperature service.
Mechanical properties of stainless steels to BS EN 10217-7 for welded stainless steel tubes for pressure purposes.
Stainless steels are alloys and therefore do not melt and freeze at a fixed temperature, as do metallic elements, but over a temperature range, depending on the chemical composition of the steel. Melting range does not directly affect the creep strength or oxidation resistance of individual stainless steels. A table of melting ranges for some of the common stainless steel grades is shown.
Summary of links to websites for download of stainless steel grade datasheets