Ionprocessing:

A new concept in commercial heat treating. The following information will give a better understanding of the various aspects of Ionitriding and its capabilities as well as its cost-saving functionalities.

• Materials that can be Ionitrided include High Speed Steels, Mould, Tool & Die Steels, Stainless Steels, Alloy Machine Steels, Carbon Steels and Cast Irons.

• Brazed and silver soldered parts containing volatile metals( cadmium and zinc) must be avoided; silver brazed parts suffer from reduced strength after Ionitriding.

• Select material and a hardness level that during Ionitriding will not change dimensionally or drop in hardness. A part hardened and double tempered at 1050 F, or higher, ensures stability in Ionitriding. To achieve the optimum hardness for a material it should be used in a heat treated condition. For hardening use only a vacuum furnace.

• Specify stress tempering before final machining at 1050 F to ensure minimum distortion in lonitriding, especially on thin, asymmetrical and heavily machined parts.

• For maximum stability of air hardening High Speed Steels, Mould, Tool & Die Steels and Stainless Steels a Cryogenic Treatment should be incorporated into the hardening process, usually after the first temper.

• Indicate areas to be lonitrided, masked and where optional; threads are masked unless otherwise specified. Critical surfaces to be Ionitrided must be clean bare metal, free from burrs, very fine sharp edges, de-carb and any form of treatment oxide or residue; lonitriding an RMS 15-30 surface is more effective than a rough or mirror finish.

• E.D.M. machined surfaces to be lonitrided must be free of re-cast layer and after E.D.M. machining all parts must be stress tempered; E.D.M. surfaces can be polished or given a fine abrasive grit blast to remove oxides.

• When a polished finish is required, use a water soluble polishing compound, preferably a diamond paste. Do not use compounds containing silicones.

• Incorporate features to allow stacking and handling lugs or threaded holes in heavy parts. Avoid sections with less than 30 degree angles, narrow slots, small blind holes and holes that exceed a ratio of length 10 times diameter.

• Blow out all threaded & blind holes and areas that may hold dirt or metal fragments. Do not supply parts contaminated with paint, plastics, rubber, residual salts from heat treat, chrome plating or containing volatile metals, i.e., Brass, Zinc alloys and plating.

• Packaging must be provided to prevent parts being damaged during transportation. A light coating of water soluble oil should be applied to prevent parts rusting. Highly-polished surfaces should also be wrapped with a plastic packaging film( food wrap).

• Purchase orders should state lonitriding specifications, materials, part and serial numbers, history of previous processes and note when dis-colouration is not permitted, e.g., Part # S-187, 4140 Rc 28-32, lonitride 0.010" - 0.015" T.C.D., Surface Hardness Hv 550-653 per AMS 2759/8.