Materials commonly used stem
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Materials commonly used stemThursday, 15 July 2021
Copper alloys: generally used grades are QA19-2, HPb59-1-1. For nominal pressure less than or equal 1.6MPa, temperature less than 200 degrees and low pressure valves.
Carbon steel : generally used in A5, 35 steel, through nitriding treatment , for nominal pressure 2.5MPa or less ammonia valves , water, steam and other media of low and medium pressure valves.
A5 steel for the temperature does not exceed 300 degrees valves ; 35 steel for the temperature does not exceed 450 degrees . ( Note: Solid line shows that stem manufactured using carbon steel nitriding can not solve corrosion problems should be avoided . )
Alloy : generally used 40Cr, 38CrMoA1A, 20CrMo1V1A other materials. After 40Cr chrome plated , for nominal pressure less than or equal 32MPa, temperature of 450 degrees or less of water , steam, oil and other media. 38CrMoA1A after nitriding treatment, can work under the conditions of temperature 540 degrees to withstand the pressure of 10MPa , commonly used in power station valve. 20CrMo1V1A after nitriding treatment temperature of 570 degrees in working condition to withstand the pressure of 14MPa , commonly used in power station valve.
Stainless steel: generally used 2Cr13, 3Cr13, 1Cr17Ni2, 1Cr18Ni12Mo2Ti other materials. 2Cr13, 3Cr13 stainless steel for nominal pressure less than or equal 32MPa, temperature of 450 degrees or less of water, steam and weak corrosive medium , can be chrome, and other methods to enhance the surface induction hardening . 1Cr17Ni2 stainless steel valves , cryogenic valves , the ability of corrosive media. 1Cr18Ni9Ti, 1Cr18Ni12Mo2Ti acid-resistant stainless steel used in the nominal pressure is less than equal to 6.4MPa, temperature is less than equal to 600 degree heat valve can also be used for temperature less than or equal -100 degrees stainless steel valves , cryogenic valves . 1Cr18Ni9Ti ability nitric acid and other corrosive media ; 1Cr18Ni12Mo2Ti ability acetic acid and other corrosive media. 1Cr18Ni9Ti, 1Cr18Ni12Mo2Ti for high temperature valves , can be nitrided to improve scratch resistance .
Bearing chrome steel : use GCr15, for nominal pressure less than or equal 300MPa, the temperature of 300 degrees or less high pressure valves . More material for the production of the stem , as well as 4Cr10Si2Mo martensitic steel , 4Cr14Ni14W2Mo austenitic heat-resistant steel. Stem nut threadedly mate with the stem , stem directly bear axial force , and licensing and stent valve friction among . Therefore, in addition to the stem nut to have a certain strength , but also requires a low friction coefficient, does not rust , and other properties are not killed with the stem.