The purpose of tempering stainless steel tube
is to transform quenched martensite into tempered martensite, eliminate retained austenite, reduce and eliminate internal stress, obtain high hardness, wear resistance and red hardness, stabilize dimensional and improve mechanics. Its performance to meet the needs of its work. Generally, the tempering temperature is generally between 540 ~ 570°C
, and it is kept in the 100% KNC)3 salt bath for 1 to 1.5 hours. Due to the tempering of high-speed steel, the fine carbides of W, Mo and V are precipitated in the martensite, and the residue remains. Austenite transforms into martensite during the III fire process and therefore has a "secondary hardening" phenomenon, which should be tempered three times.
In order to ensure the tempering effect of high speed steel, the following issues should be noted:
1 After the stainless steel tube is quenched, it should be tempered immediately, otherwise the retained austenite will be stabilized, which is not conducive to the elimination of retained austenite.
2 The tempering temperature should be uniform, it is recommended to carry out in the salt furnace.
3 stainless steel pipe must be cooled to room temperature after each tempering, in order to carry out the next tempering.
4 After the tempering for stainless steel tube, the cutter should be cooled to room temperature to be cleaned, otherwise the stainless steel tube may be cracked.
The high-temperature resistant stainless steel pipe is used for dry burning. Under the condition of not exceeding the extreme temperature of the high-temperature resistant stainless steel pipe, the problem of using the high-temperature resistant stainless steel pipe for dry burning will not be great, but this will greatly shorten the service life of the high temperature resistant stainless steel pipe. The use of a cooling liquid in the center of the high temperature resistant stainless steel pipe will increase the service life of the high temperature resistant stainless steel pipe, so it can be known that in order to ensure the service life and performance of the high temperature resistant stainless steel pipe, it is preferable not to use dry burning of the high temperature resistant stainless steel pipe.