Effect of Tempforming Temperature on the Impact Toughness of an HSLA Steel

The fracture behavior of a high-strength low-alloy steel subjected to tempforming at 873 K, 923 or 973 K was studied by means impact and bending tests. A decrease in temperature promoted the grain refinement resulting ultrafine grained lamellar-type microstructure with finely dispersed particles that led significant strengthening along an increase toughness. tempformed samples exhibited Charpy V-notch energy well above 100 J temperatures 183–293 due delamination rolling plane during bending, which attributed high anisotropy cleavage stress. Delamination owing easy crosswise direction blunted primary crack resulted zigzag propagation, leading Depending on temperature, three types were observed specimens upon three-point tests room temperature. Namely, early, restrained, late delaminations took place after tempering respectively. On one hand, test delamination, other lowering is accompanied suppression ductile fracture. sample highest toughness whereas 923–973 characterized higher 183–233 K.