GPI - Product Catalogue FORGE

Transcription

1 GPI - Product Catalogue FORGE Regd.Office & Works : P.O. Pailan, Diamond Harbour Road, 24 Parganas(S),West Bengal,India, Pin : Phone : / 56, / 8294, Fax: / 8686, Website :

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3 Product Information Sheet Induction Hardened Alloy Forged Steel Rolls Alloy Forged Rolls are generally used as Work Rolls for 4 High Tandem Cold Rolling Mills, Work Rolls & Intermediate Rolls for 6 High Reversing & Tandem Cold Rolling Mills. Forged rolls are also used as Work Rolls for single stand and Multi Stand cold rolling temper mill. To achieve the above properties, Forged Steel blanks undergo a series of stringent Heat- Treatment process consisting of Homogenizing, Spherodising, Normalizing or Volume Hardening (depending on the process requirements) & polymer Quenching & Stress relieving to minimize internal stresses This is followed by low frequency Induction Hardening and post Induction Hardening Tempering (in a re-circulation furnace) to ensure barrel hardness in the range of 90 to 100 Sh D, JIS (which corresponds to LE) For further stabilizing the microstructure the induction hardened rolls are subjected to Sub-Zero Treatment by quenching in liquid nitrogen Throughout the manufacturing process stringent process control measures are adopted to ensure specified quality requirements. Heat Treatment Capability Drop in Hardness Radial Depth Hardening Method Work Roll Work Roll Special Progressive type 8-10 ShD 30 mm Induction Hardening Intermediate Roll Intermediate Roll 3-5 ShD 35 mm Typical Carbide Analysis Carbide Type Carbide Hardness Surface Area Average Diameter HV % M3C/M7C3 ( )/( ) Regd.Office & Works : P.O. Pailan, Diamond Harbour Road, 24 Parganas(S),West Bengal,India, Pin : Phone : / 56, / 8294, Fax: / 8686, Website :

4 Forged Steel Back up Roll 500 X Nominal Chemical Composition [in %- wt] & Mechanical Properties [1 MPa = 1 N/mm2 (=0.1 kgf / mm2 )] Element %C %Si %Mn %P %S %Cr %Ni %Mo Tensile Strength of Journal (MPa) Bending Strength of Journal (MPa) Barrel Hardness in ShC Min Max max max 5.00 max Hardness in Depth [SH C] HARDNESS (in ShC)--> DEPTH FROM SURFACE (mm)--->

5 Product Information Sheet Forged Steel Back Up Roll Alloy steel forged BUR are made from special quality steel manufactured from quality raw material & ferroalloys through secondary refining& ingot pouring. The ingots are hot forged and dehydrogenation treatment is carried out. Forged blanks are procured and going through stringent quality inspection in macro & micro aspects and then processed successive stages of heat treatment like homogenizing, normalizing to improve the overall structural soundness, stress distribution uniformity & toughness. It undergoes differential hardening process followed by mist quenching or compressed air quenching depending on the hardness requirement upto a desired depth on barrel surface only.the tempered roll exhibits a uniform bainitic microstructure at the shell & fine pearlitic structure at the core /neck. Due to the differential hardening the barrel / working area up to a critical depth only reaches to critical temperature & hence hardened. The rest core & neck remains unaffected resulting higher impact strength as well as strength against overload during the rolling The above rolls are of following applications- Hot & cold mills Back-Up rolls Continuous & Semi-Continuous hot strip mills Back-Up rolls Roughing 4-High stands Back-Up rolls Cold tandem mills Back-Up rolls Thick plate mill Back-Up rolls These rolls are characterized by the following properties : Higher hardness penetration Improved Wear Resistant property - To provide higher campaign life Higher toughness property - To provide more resistance to spalling & fatigue Recommendations for usage : After each rolling campaign the roll barrel surface should be thoroughly ground to regain original supplied hardness. (max hardness increment of 2 ShC is allowed) Between these two varieties choice to be made on the basis of mill conditions as performance superiority of forged quality roll may get deteriorated due to mill abnormality.