Posted by deepak desai on January 22, 2010 at 02:03:59:
We are carrying Quench & Temper HT to our cylinder of Cr-Mo Grade. Cr-0.8/1.2 & Mo-0.15/0.3 C-0.34/0.38 Mn-0.5/0.8. The HT Carrying at 930Deg C & Quench in Polymer solution 12% Concentration.The toal cycle time for cylinder remain in furnace 60/65minutes. As quench Hardness we are getting 350-425 BHN. In quenching tank agitation also there.Microstructure reveals ferrite / Pearlite with martensite. What will the cause of ferrite.No retained austenite found.Temperature after quenching 40 to70 DegC.
We are cylinder manufactuerer this problem face in 90 lit cylinder. 317mmDia x 7.4 mmthk & 1200mmlength cylinder whose weight 95 Kgs.Will you pl suggest the cause of low hardness