Fracture Analysis of High Chromium Cast Iron Roll on CSP Mill

A roll barrel breakdown accident took place on CSP mill. After investigating of the accident scene and the roll service condition, analysing the barrel fracture and sampling tests, proved that main cause for the roll breakdown was unusual and there appeared a strip-like crack on the boundary layer resulting from the initial flaws extending along the roll circle direction; furthermore, the flaws caused fatigue breakage along the roll inner cross section, which resulted in the barrel breakdown.

ACI TYPE HP

Type HP is an iron-chromium-nickel alloy with a combination of elements that makes it resistant to both oxidizing and carburizing atmospheres at high temperatures. The alloy has good creep-rupture properties in the 1800-2000 F temperature range. It has an austenitic structure at all temperatures, thus it is not susceptible to embrittlement from sigma phase formation. Type HP was developed for rugged steel-mill furnace-roll service; no comparable wrought alloy exists. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: SS-307. Producer or source: Stainless steel foundries.