Surface finish Tempering

With all due respect to the metallurgical characteristics, temper, thickness, or material shape, over which the slitter has no control, the quality of the slit strand is still a function of its edge condition, accuracy of width, flatness or crosscurvature, camber, and surface finish. 

Raw material factors include chemical composition, form of mill product, size of mill product, material condition or temper, surface finish, and quality characteristics. 

Stainless steel ways are usually made from austenitic cold-finished bars or strips. Stainless steel offers the best corrosion resistance. They should have a surface finish of 32 to 63 microinches Ra and shonld have a one-quarter hard temper with a hardness of 25 to 35 Rc. Softer annealed grades of anstenitic stainless steel should be avoided because they will not have the abrasion resistance of the one-quarter hard temper. 

Fig. 3.6 Experimental data obtained by Siebel and Gaier on surface finish effect on quenched and tempered and annealed steels [2]...

Copper Strips—Use strips 12.5 mm ( A in.) wide, 1.5 to 3.0 mm ( /i6 to Vs in.) thick, cut 75 mm (3 in.) long from smooth-surfaced, hard-tempered, cold-finished copper of 99.9-1- % purity. Electrical bus-bar stock is generally suitable (hard-temper, cold-finished type-electrolytic tov pitch (ETP) copper conforming to UNS Cl 1000 in Specification B 152. Drill a 3.2-mm ( /s-in.) hole approximately 3.2 mm ( /s in.) from one end in the center of the strip. The strips... 

Therefore the reaction rate for an in situ surface modification during a moulding process has to be very fast, as can be concluded from the model assumption in Fig. 18. The chemical coupling of substances has to be finished after a very short time because at the moment of contact of the hot melt front with the tempered or rather "cold" mould surface the temperature drops rapidly and as a result an exponential decrease of the reaction rate should be observed (Arrhenius equation). 

Tempering of glass has been well established for decades but very little work has been done in the area of container glass. This is due to the difficulties associated with rapidly cooling the inside surfaces of the container through the limited opening of the finish, the wall thicknesses and variations thereof, and due to the complex geometries involved. 

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