3 Fundamentals of press design

Metal Forming Handbook / Schuler (c) Springer-Verlag Berlin Heidelberg 1998
Table 4.1.3: Specifications and applications for surface hardening and coating of dies
SURFACE HARDENING PROCESSES COATING PROCESSES
electrical physical CVD process hard chromium PVD process
induction hardening flame hardening glow nitriding Ti C Ti C - Ti N plating Ti N Cr N Ti C N
Method hardening temperature hardening temperature inclusion of nitrogen combination of hardening and coating application of heating to coating temperature below 500 °C,
through high- through acetylene through electrical process: hardening of the base chrome coat in vacuum coating, vacuum cooling,
frequency induced oxygen flame discharge in a material to approx. 60-62 HRC, vacuum, diffusion distortion-free process
eddy currents vacuum coating > 1 000 °C, or electrical preaustenitizing,
tempering cipitation at
around 100 °C
Usable unalloyed and alloyed unalloyed and alloyed all ferrous materials ledeburitic chromium steels, carbides cast iron, steel, cold and hot work steels, HSS, carbides,
workpiece steels 0.2 - 0.6 % C steels 0.2 - 0.6 % C non-ferrous metals rust-proof steels
material e.g. Ck 45, e.g. Ck 45, e.g. 1. 2379, 1.2842, preferably 1.2379 e.g. 1. 2379, 1. 2601, 1. 2369, 1. 2378
50 Cr Mo 4 50 Cr Mo 4 1.2601, 1.0062, 0.6025,
1.7131
Workpiece metalically metalically finish machined, metalically bright and polished metalically bright electrically conductive, non-magnetic condition,
requirement bright surface bright surface metalically surface, roughness R z < 3 µm, non- surface, no material, no shrinkage in case of soldered parts,
bright surface functional surfaces (fitting surfaces) processing or sur- metalically bright surface, roughness
with allowance, specification of face faults, as a rule R z = 2 - 4 µm, no burr, no assembled parts
tolerance field in the drawing prior to surface
hardening
Layer 53 - 59 HRC, hardening wear-resistant approx. 1200-1 400 HV2, approx. 4 000 HV, approx. 3 000 HV, 600 - 1 100 HV0,1, approx. 2 400 HV, approx. 2 000 HV, approx. 3 000 HV,
character- depth 1,5 - 3 mm, surface, workpiece improvement of max. charging max. charging rustproof surface, max. charging max. charging max. charging
istics wear-resistant surface, core with high sliding properties, temperature 300 °C, temperature increased wear temperature temperature temperature
workpiece core with toughness, danger of increase of strength, brittle, layer thick- approx. 450 °C, resistance, good approx. 500 °C, approx 600 °C, approx. 400 °C,
high toughness, scaling, following increase of ness up to layer thickness coefficients of chemical resis- good chemical resis- layer thickness
following finish finish surface roughness approx. 9 µm, up to approx. friction, max. layer tance, layer thick- tance, layer thick- up to 3 µm,
�R a = 0.1–0.3 µm grey metal colored 9 µm, grey thickness ness up to 3 µm, ness up to 50-70 µm, brown-violet
metal colored 100 µm gold colored silver colored
active parts of forming and active parts of blanking and separating dies
drawing dies and machining tools
Range of cast blanking cutters, lifting bolts, all wear active primarily for primarily for draw punches, primarily non-ferrous metals primarily for
parts gib rails, gib elements, die parts and thicker uncoated aluminium plated female dies, unalloyed and Cr Ni steels low and high
partial draw cast blanking cutters, gib elements sheet steels and galvanized blank holders deep-drawn alloyed steels,
punches and partial draw sheet metals sheets e.g. VA sheet
female dies punches and
female dies
metals
146 Sheet metal forming and blanking