The valve stem opening and closing process, to withstand tensile, compressive and torsional forces, and in direct contact with the media, and also to the friction between the filler and the relative movement, so the stem material must ensure that the required temperature for a sufficient strength and toughness, a certain resistance to corrosion and scratch resistance, and good manufacturability.

Stem material commonly used are the following:

First, carbon steel for low and medium temperature does not exceed 300 ℃ of water, steam medium, generally used in A5 ordinary carbon steel . For medium and medium temperature does not exceed 450 ℃ of water, steam medium, generally used in 35 high-quality carbon steel .

Second, the steel used in medium and high pressure , medium temperature does not exceed 450 ℃ of water, steam , oil and other media, generally used in the 40Cr ( chrome steel ) . For high pressure, medium temperature does not exceed 540 ℃ of water, steam and other media , the choice 38CrMoALA nitriding steel . For high pressure, medium temperature does not exceed 570 ℃ steam medium, generally used 25Cr2MoVA chromium molybdenum vanadium steel.

Third, acid-resistant stainless steel used in medium and high pressure , medium temperature does not exceed 450 ℃ non- corrosive medium and weak corrosive medium , the choice of 1Cr13, 2Cr13, 3Cr13 chromium stainless steel . For corrosive media , the choice Cr17Ni2, 1Cr18Ni9Ti, Cr18Ni12Mo2Ti, Cr18Ni12Mo3Ti other acid-resistant stainless steel and PH15-7Mo precipitation hardening steel.

Four , heat-resistant steel used in medium temperature does not exceed 600 ℃ high temperature valves , the choice 4Cr10Si2Mo martensitic heat-resistant steel and 4Cr14Ni14W2Mo austenitic heat-resistant steel.

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