THE STRUCTURES AND PROPERTIES OF ROLLED 0.18-PERCENT PLAIN CARBON-STEEL STRIP PRODUCED BY LIQUID DYNAMIC COMPACTION

Liquid dynamic compaction (LDC), a spray deposition process which yiel ds as-deposited sprayed densities of 96+/-3% against a water cooled mi ld steel substrate, was applied to the production of low (0.18 wt.%) c arbon, plain carbon steel sheet and strip. Resultant as-deposited mate rials showed fully crystallized, fine grained (10 to 40 mum, on averag e) structures. Cooling rates during solidification were about 10(3) K/ s and solid state cooling rates were 10(1) to 10(2) K/s depending on s pray forming variables. The as-spray-deposited plates were warm rolled to full density at 700-degrees-C (873 K) in the ferrite plus carbide region and hot rolled at 1050-degrees-C (1323 K) in the austenitic sta te. Less than a 70 per cent reduction was required to achieve full den sity in 2 to 3 passes. The resultant grain sizes of 1 to 10 mum were a function of the total reduction, with emphasis on the reduction in th e final pass. A variety of simple heat treatments were utilized, resul ting in increases of 25 to 50 per cent in yield and ultimate tensile s trength values at high levels of ductility as compared to properties o f the same grade of steel produced by ingot technology, continuous cas t thick slabs, and plates spray deposited against preheated substrates .