Cold forgeability

Directorate-General For Translation European Commission

Description

Industrial research and development

Informations

• Publié par: EUROPEAN-COMMISSION
• Nombre de lectures: 3
• Langue: English
• Poids de l'ouvrage: 3 Mo

Extrait

ψ ,*2~\:-
Commission of the European Communities
technical steel research
Properties and service performance
Cold forgeability Commission of the European Communities
technical steel research
Properties and service performance
Cold forgeability
R.F. Dewsnap
BSC London
Contract No 6210-KC/8/802
(1.4.1975 - 30.9.1978
FINAL REPORT
Published by the Directorate-General
Information Market and Innovation
1982 EUR 7617 EN Published by the
COMMISSION OF THE EUROPEAN COMMUNITIES
Directorate-General
Information Market and Innovation
Bâtiment Jean Monnet
LUXEMBOURG
LEGAL NOTICE
Neither the Commission of the European Communities nor any person acting
on behalf of the n is responsible for the use which might be made of
the following information
IECSC-EEC-EAEC, Brussels ■ Luxembourg EUR 7617 EN 6210 .KC.8/802
SUMMARY
Cold forging is a high productivity operation placing
stringent demands on material requirements. In view of the in­
creasing complexity of cold forged shapes the principal require­
ments are that thel should possess adequate flow
properties at high levels of strain accompanied by the ability
to sustain ah level of deformation without cracking. A
further requirement is that the material should have a low
resistance to deformation, thus reducing press loads, hence
minimising plant capacity requirements and tool wear.
Steels for cold forging applications cover a diverse range
of compositions from low carbon unalloyed to medium carbon and
alloyed grades having hot rolled microstructures from ferrite-
pearlite to martensite. While the low carbon unalloyed steels
may be suitable for cold forging with a minimum of pre-conditio­
ning the carbon and alloy grades require some form of heat
treatment, generally of the spheroidisation anneal type. The
softening behaviour of a range of steels has been examined and
the response of various microstructural types from ferrite-
pearlite to ferrite-spheroidised carbide has been studied in the
two principal forging modes, unsupported backward extrusion
(penetration testing) and injection upsetting. Of the two tests
injection upsetting gives the more reproducible results due to
the difficulty of detecting internal cracks in the penetration
test.. Low carbon steels gave the better performance in both
tests, non-metallic inclusions being the dominant controlling
factor.
These steels also show relative insensitivity to surface
defects. In contrast the higher carbon steels were less fortnable
being dependent principally on carbide volume fraction and
showing marked sensitivity to surface defects. Useful correla­
tions have been established between tensile ductility properties
and performance in the two cold forgeability tests. 6210.KC.8/802
CONTENTS
Page
1. INTRODUCTION 1
2. MECHANICAL TESTING AND QUANTITATIVE 1
METALLOGRAPHIC TECHNIQUES
2.1 Tensile Tests
2.2 Metallography
2.3 Cold Forgeability Tests 2
2.3.1 Injection Upset Test
2.3.2 Penetration Test 3
2.3.3 Details of Testing Conditions 3
3. MATERIALS 4
3.1 Steel Composition
3.2 Heat Treatments and Microstructures 4
3.2.1 Steel 1 (0.1°/o C) 5
3.2.2 Steel 2 (0.2% C) 6
3.2.3 Steel 3 (0.4% C)
3.2.4 Steels 4 and 6 (0.l8% C - 0.8% Cr; 7
0.l6% C-Ni-Cr-Mo)
3.2.5 Steels 5 and 7 (0.35% C - 1% Cr;
O.035°/o)
3.2.6 Response of Steels 4-7 to Quench 7
and Temper Treatments
4. RESULTS 8
4.1 Tensile Properties
4.2 Cold Forgeability Tests
4.2.1 Injection Upset Test 8
4.2.2 Penetration Test 10
4.2.3 Forming Loads2
4.2.4 Surface Strain Measurements 1
111 6210.KC.8/802
Page
5. DISCUSSION 13
5.1 Heat Treatments I5
5.2 Tensile Properties l6
5·3 Cold Forgeability Assessment 17
5.4 Forming Loads 20
5.5 Surface Strains in Forging1
6. CONCLUSION - 22
7. REFERENCES3
TABLES 1-10
FIGS. I-30
IV 6210.KC.8/802
LIST OF TABLES
1. Analyses of Experimental Steels
2. Softening Heat Treatments Used for Low and Medium Carbon
Steels Prior to Cold Forging
3. Details of Heat Treatments Used
4. General Microstructural Data
5. Inclusion Characterisation
6. Hardness Values for Quenched and Tempered Samples
7. Tensile Properties
8. Results of Injection Upset Tests
9·s of Penetration Tests
10. Surface Strain Measurements