ISSN 2594-5297
41º Seminário de Laminação, Processos e Produtos Laminados Revestidos — vol. 41, num.41 (2004)
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High Speed Steel (HSS) cast rolls are used in front finishing stands of hot strip mills (HSM). Good wear resistance and hardness at high temperatures, are defining features of HSS. Previous experience has shown that HSS rolls containing mainly hard MC carbides have a high friction coefficient, which is detrimental for the rolling power consumption and for the strip surface quality. On the other hand, HSS rolls containing eutectic rod shaped carbides are brittle and more susceptible to spalling. To overcome these problems, a suitable grade, called HSS7, that gives the best compromise between a low friction coefficient and a high crack propagation and wear resistance was developed. That alloy contains well-dispersed hard VC carbides improving wear, and non-interconnected eutectic carbides of the M2C and M7C3 type, hindering crack propagation. All the metallurgical factors affecting the performance and damage of under rolling condition in front finishing stands are reviewed: wear resistance, friction coefficient, resistance to rolling incident, and oxide film formation. The effect of nature, morphology and amount was for each of the carbides studied and connected to the factor affecting the behaviour of the new grade developed. Different techniques are used such as: differential thermal analysis, optical and electron scanning microscopy and image analysis. A correlation with mechanical properties was also performed.
High Speed Steel (HSS) cast rolls are used in front finishing stands of hot strip mills (HSM). Good wear resistance and hardness at high temperatures, are defining features of HSS. Previous experience has shown that HSS rolls containing mainly hard MC carbides have a high friction coefficient, which is detrimental for the rolling power consumption and for the strip surface quality. On the other hand, HSS rolls containing eutectic rod shaped carbides are brittle and more susceptible to spalling. To overcome these problems, a suitable grade, called HSS7, that gives the best compromise between a low friction coefficient and a high crack propagation and wear resistance was developed. That alloy contains well-dispersed hard VC carbides improving wear, and non-interconnected eutectic carbides of the M2C and M7C3 type, hindering crack propagation. All the metallurgical factors affecting the performance and damage of under rolling condition in front finishing stands are reviewed: wear resistance, friction coefficient, resistance to rolling incident, and oxide film formation. The effect of nature, morphology and amount was for each of the carbides studied and connected to the factor affecting the behaviour of the new grade developed. Different techniques are used such as: differential thermal analysis, optical and electron scanning microscopy and image analysis. A correlation with mechanical properties was also performed.
Palavras-chave
Carbides, microscopic identification, HSS.
Carbides, microscopic identification, HSS.
Como citar
Lecomte-Beckers, Jacqueline;
Tchuindjang, Jerome Tchoufang;
Ernst, Roger;
Breyer, Jean-Pierre.
Structural Investigations of HSS Rolls for Hot Strip Mill
,
p. 89-98.
In: 41º Seminário de Laminação, Processos e Produtos Laminados Revestidos,
Joinville - SC,
2004.
ISSN: 2594-5297
, DOI 10.5151/2594-5297-0009
