Vergleichsstudie martensitischer korrosionsbeständiger Stähle
Research output: Thesis › Master's Thesis
The aim of this diploma thesis is to investigate the mechanical properties and the corrosion behaviour of martensitic, corrosion resistant steel-grades in two different tempering conditions to complete the previously known range of properties. The studies were performed on two conventionally produced grades and two nitrogen-alloyed, remelted qualities. In order to investigate the mechanical properties of steel grades, tensile tests, hardness tests, impact tests and KIC-measurements were carried out. Concerning mechanical properties, higher tempering temperatures at the same austenitizing temperature generally led to a higher fracture and tensile strength as well as to increased hardness. In high tempered condition some tested grades exhibited lower yield strength than in low tempered condition despite their higher tensile strength in the high tempered condition. During impact tests, the remelted nitrogen-grades achieved the highest level of toughness, regardless of tempering temperature. However, conventional produced steel-grades have shown the highest values of crack fracture toughness. The corrosion studies included immersion testings in acetic acid, the determinations of the current density-potential-curves and salt spray tests. Low tempering resulted in better corrosion resistance in all grades than in the case of higher tempering temperatures. Especially the remelted nitrogen-grades showed very high corrosion resistance.