normalize intercritical heat treatment draw over mandrel intercritical heat treatment q amp t heat treatment the first of these processes corresponds to a standard method of manufacture for this grade tubular where a hot formed tube is heat treated to the proper strength range the second process includes the applicant 39 s intercritical heat treatment and cold working steps described herein but is otherwise identical as described below tube samples from each of these processes were tested according to the nace tm 01 77 standard test method for characterization of their resistance to failure by sulfide stress cracking heats having chemistries as shown in table iv below were prepared in an electric arc furnace using a double slag process and continuously cast into 12 486 inch modified square blooms for piercing and extrusion table iv______________________________________constitutent heat 63910 heat 73355______________________________________carbon 0 30 0 32manganese 0 57 0 79phosphorus 0 016 0 009sulfur 0 021 0 011silicon 0 25 0 34copper 0 24 0 21chromium 1 20 1 03molybdenum 0 54 0 24nickel 0 14 0 10tin 0 012 0 009vanadium 0 096 0 12aluminum 0 004 0 005______________________________________ the blooms were pierced and then extruded to a diameter of 7 8 inches on two occasions first to assess the efficiency of the martensitic transformation upon quenching tubulars were extruded for nominal 75 8 inch od having 0 500 and 1 200 inch wall thicknesses these tubulars were austenitized for about 45 minutes at 1675 u00b0 f and simultaneously inside and outside water quenched to 200 u00b0.