Download or read book Study of Undermatched Welds in HSLA 100 Steel written by and published by . This book was released on 1998 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes and presents results from tensile and fracture toughness tests conducted to determine whether undermatched welds (those made with weld consumables not matching the strength of the base plate) have lower joint efficiency and higher crack driving force because of increased strain concentration near weld metal flaws. Mismatched welds were fabricated by over-ageing 15-millimetre HSLA100 steel plate to four reduced yield strengths, and then using the same shielded-metal-arc welding consumable and procedure to make five welds with different degrees of under- and overmatch between -30% and +16% of yield strength but having the same weld metal toughness. Wide cross-weld tensile specimens were tested with and without reinforcement, and full thickness fracture toughness tests were performed at various sub-zero temperatures using nominal fatigue pre-crack/specimen width ratios of 0.17 and 0.5. The tensile tests indicated the tolerable level of ultimate strength undermatch for fracture outside the weld metal in the absence and presence of weld reinforcement. For the fracture toughness tests, two different sets of equations were used to calculate the crack driving force. Statistical analysis of the results was used to show effects of metal mismatch on measured weld metal fracture toughness.