The properties of a 0.45 Pct V steel pipe and the effects of some variation in composition

Abstract

It can be concluded that 1219 mm (48 in) OD x 15 mm (0.60 in) pipe to API specification 5LS706 pipe for Arctic service can be produced from steel containing 0.06 pct C, 1.9 pct Mn, 0.45 pct V, and 0.06 pct Mo when the plate is reheated to 1230 °C, rolled on a fairly light mill and made into spiral pipe. Tests on sections of one of the slabs used in this trial when rolled in a laboratory mill at Canada Centre for Mineral and Energy Technology (CANMET) with two reheating temperatures of 1150 and 1250 °C showed that with a reheating temperature of 1150 °C the plate had a 20 °C lower transition temperature. It is, therefore, possible that pipes with improved toughness could be achieved if a lower reheating temperature was used in the production rolling. It would also appear that although adequate weld metal toughness was achieved for Arctic grade pipe when using standard manganese molybdenum wire and a basic flux, improved toughness was obtained on an experimental weld when using a ‘Tibor 22’ wire. Further data from experimental heats indicated that welds of improved toughness could be produced in a steel with lower, more usual, nitrogen contents and that this would not alter the strength or toughness of the pipes under given rolling conditions. Furthermore, tests on plates from one of the ingots rolled with heavier reductions in the primary rolling stage gave higher strength from which it would appear that higher strength grades than x 70 could be produced from this steel with suitable rolling schedules.