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Good afternoon , I'm looking for any information comparing test results from ASTM E8 tensile, or E23 Charpy impact, hardness mapping, ASTM E381 macro etch, and ASTM inclusion ratings to determine if ingot cast 4140 or 4340 consistently shows better toughness, lower segregation, or more uniform properties, than continuous cast, that would indicate metallurgical superiority of the Ingot cast material.  

Reduction ratio and magnetic stirring of continuous cast strand are variables to consider.

Good afternoon , I'm looking for any information comparing test results from ASTM E8 tensile, or E23 Charpy impact, hardness mapping, ASTM E381 macro etch, and ASTM inclusion ratings to determine if ingot cast 4140 or 4340 consistently shows better toughness, lower segregation, or more uniform properties, than continuous cast, that would indicate metallurgical superiority of the Ingot cast material.  

Good afternoon , I'm looking for any information comparing test results from ASTM E8 tensile, or E23 Charpy impact, hardness mapping, ASTM E381 macro etch, and ASTM inclusion ratings to determine if ingot cast 4140 or 4340 consistently shows better toughness, lower segregation, or more uniform properties, than continuous cast, that would indicate metallurgical superiority of the Ingot cast material.  

Hello Richard,

This type of data was generated back when the continuous casting process was in development. You may refer to old literature to obtain specific data. In general, the mechanical properties would depend on section thickness of the final product, heat treatment and the end application. 

The ingot derived products, in most cases, yield superior properties. This is due processing of the ingot. Ingots are cast vertically in large sections, with heat being extracted from the  bottom while maintaining hot top. This results in shrinkage porosity and impurity segregation at the top of the ingot. The solidification takes place directionally in the long direction. The ingot is then trimmed to remove surface skin and top region before hot rolling commences. Since the reduction in area during hot rolling is large in the ingot derived products, a finer and more uniform microstructure is obtained. In general, an ingot derived product will have the following advantages over the continuous cast products:

• Higher transverse strength
• Lower inclusion concentration
• Finer inclusion size
• Finer carbides
• Higher toughness, particularly in the transverse direction
• Higher fatigue strength
• Higher uniformity across thickness

The continuous cast products are produced in smaller cross section size and, therefore, do not undergo high reduction in area during hot rolling like the ingot derived products. As a result, the microstructure is not subjected to extensive breakdown typically seen with the ingot derived products. Also, due to the nature of the process, the segregations and inclusions are trapped in the center of the continuous cast billet. 

You may see comparable properties from the two processes when the reduction in area during hot rolling is comparable and critical properties for service use are longitudinal.

Please refer to old journals for more information. The steel suppliers will also have this information in their product portfolio.

Good Luck!

Ratnesh Dwivedi, Ph.D.

RKD ENGG, LLC

www.rkdengg.com

Good afternoon , I'm looking for any information comparing test results from ASTM E8 tensile, or E23 Charpy impact, hardness mapping, ASTM E381 macro etch, and ASTM inclusion ratings to determine if ingot cast 4140 or 4340 consistently shows better toughness, lower segregation, or more uniform properties, than continuous cast, that would indicate metallurgical superiority of the Ingot cast material.