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Technical requirements for important forgings such as couplings for steam turbines

Publisher: Ever-Power Mechanical Equipment
2014-06-18

 For steam turbineCouplingTechnical requirements for important forgings

1、化学成分要求。钢的化学成分分析按GB/T223-2000的规定进行;成品分析由需方进行。其偏差按GB/T222-1984的规定。
2. Coupling mechanical properties and test requirements
(1) Performance requirements: The tensile, impact and brittle transition temperature of forgings are in accordance with Table 9-67.
(2) Tensile test: The tensile test is carried out in accordance with the provisions of GB/T228-2002
(3) Impact test: The impact test is carried out in accordance with the provisions of GB/T229-1994.
(4) Brittleness transition temperature test: When there is a requirement on the demand-side forging drawing, the forging shall be determined according to JB/ZQ6117. FATT50.
(5) Hardness uniformity inspection: After forgings are quenched and tempered, the hardness should be measured one by one according to the provisions of GB/T231-2004 to check their uniformity.The hardness deviation is specified as follows: at both ends or the outer surface of both ends
 
Measure one point every 90 degrees on the upper side, the hardness deviation of each point at the same end shall not exceed 30HBW, and all points shall not exceed 40HBW.Forgings with a height less than 450mm are allowed to hit one end.
(6) For forgings with a diameter less than 300mm, it is allowed to check the mechanical properties of the forgings in batches.Each batch consists of blanks with the same melting furnace number and the same heat treatment furnace (tempering furnace number).
(7) The sampling location and direction of coupling forgings shall be implemented in accordance with the requirements of the demand-side forging drawing.The sampling direction is generally tangential, and the number of samples is one tensile and two impacts.
(8) The mechanical performance test should generally be carried out after the performance heat treatment and before the stress relief. If one test item fails during the test, a double sample of the adjacent part should be taken for retry.Retry results still
 
When a test item is unqualified, the heat treatment shall be re-tested, but the number of quenching shall not exceed two.If white spots are found in the test, the forging shall be scrapped.