The quenching temperature is mainly determined according to the critical point of the wear resistant lining of high chromium cast iron.Subeutectoid steel is usually heated to 30~50℃above Ac3, while eutectoid steel and hypereutectoid steel are heated to 30~50℃above Ac1, and in some cases to 50 ~ 70℃above ^, as shown in the figure.If the quenching heating temperature of subeutectoid steel is lower than that of Ac3, then the steel has not been fully austenitized at this time, and some untransformed ferrite exists, and the ferrite remains in the quenching structure after quenching.The hardness of ferrite is low, so that the hardness after quenching can not meet the requirements, but also affect other mechanical properties.If the Ol i hatim stiel bilong subutekoid long Ac3 tempereja bilong kilim i dai, na ol i hatim ol samting bilong helpim ol samting bihain long ol i kilim i dai.Ol i bin hatim stiel bilong yutectoid antap long Ac1 long 30 ~ 50 digri.Bihain long ol liklik hap bilong bodi, na ol i bin kilim i dai long bodi bilong ol liklik hap bilong bodi, na sampela hap bilong bodi bilong ol i bin dai. i stap long wankain mak long lamellar martensait matriks.Ol dispela kain tisu i gat bikpela hat, gutpela wear resistens na liklik britelness na liklik mak bilong britelness.Kwina bilong haipereutectoid stiel i no inap stap daunbilo long mak bilong Ac1, long wanem, ol i no bin stretim gut temperaja long dispela taim bilong dispela taim.Taim ol i bin hatim long dispela taim bilong dispela taim.Taim ol i bin hatim long hat bilong en. liklik mak bilong simen i solap i go insait long austenit.Ol austenit grein i bin gutpela na kabon mass fraksen i bin antap moa long dispela bilong eutectoid.Sapos tempereja i go antap yet, seken simen bai go het long lus i go long austenit, na dispela bai kamapim bikpela gro bilong ol kwait bilong ol austenite, na dispela bai mekim na ol i wok long kamap bikpela long ol austenite, na dispela bai mekim na ol i wok long kamap strong moa long ol samting bilong dai. ol maikrokrak na britelnes.Long wankain taim, bikos long bikpela austenit kabon konten, mak bilong residual austenit i go antap bihain long em i dai, na daunim strong na wear resistens bilong wear-resistant liner.
Olsem na, pasin bilong daunim hat bilong hat bilong haipereutectoid stiel i no gutpela long stap antap tumas long Ac1, na hatim tempereja bilong Acm o antap i no stret moa .
