Effect of high temperature annealing on texture and microstructure on an AISI-444 ferritic stainless steel

• Published in: Materials characterization 2006-12, Vol.57 (4), p.342-347
• Main Authors: de Abreu, H.F.G., Bruno, A.D.S., Tavares, S.S.M, Santos, R.P., Carvalho, S.S.
• Format: Article
• Language: English
• Subjects: Carbide precipitates; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Ferritic stainless steel; Materials science; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Recrystallization texture; Rolling texture; Solidification
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2006.02.015

AISI 444 is a Mo-alloyed ferritic stainless steel which presents good naphthenic corrosion resistance, making it attractive for applications in petroleum refining plants; however, good formability is also important. To achieve good formability with this alloy the annealing process is crucial. The annealing temperature in ferritic stainless steel is usually around 850 °C, which falls in the range of sigma phase precipitation. A means to avoid this precipitation is to anneal at temperatures around 1000 °C followed by rapid cooling. Annealing at high temperatures can cause grain growth and carbide or nitride precipitation which can result in a reduction of room temperature toughness. In this paper, the rolling and recrystallization textures of AISI 444 steel were studied in samples cold rolled with different thickness reductions (30%, 60%, 80% and 90%) followed by annealing at 955, 980 and 1010 °C. Aspects of grain size and carbide precipitation after annealing were characterized using EBSD and AFM. The material drawability was analyzed through strain rate or Lankford ( r) coefficients calculated from texture results.