Исследование локального разупрочнения деформированной аустенитной Cr-Ni стали под воздействием лазерного облучения и повышение долговечности прокладок цилиндров автомобильных двигателей

• Автор: Эрб, Вилфрид Юлиус
• Шифр специальности: 05.02.01
• Научная степень: Кандидатская
• Год защиты: 2003
• Место защиты: Москва
• Количество страниц: 128 с. : ил

MOSCOW STATE INSTITUTE OF STEEL AND ALLOYS (TECHNOLOGICAL UNIVERSITY)

AS MANUSCRIPT

Studies of Local Softening of a Deformed Austenitic Cr-Ni-Steel under LASER Heat Treatment and an Improvement of Lifetime of Cylinder Head Gaskets in Automobile Engines

Speciality: 05.02.01 “Material Science in Metallurgy”

DISSERTATION FOR CANDIDATE OF TECHNICAL SCIENCES

Wilfried Julius Erb

Scientific advisor:

Doctor of physical and mathematical sciences Prof. Yu. Kh. Vekilov

MOSCOW 2
Studies of Local Softening of a Deformed Austenitic Cr-Ni-Steel under LASER Heat Treatment and on Improvement of Lifetime of Cylinder Head Gaskets in Automobile Engines.
The weak point at metal cylinder head gaskets is the limited life time of the beads. Beads may crack during the life time of an engine. Cracked beads do not seal any more in a proper way and as a consequence combustion gas may leak into water cooling system of the engine or into the oil circuit. These leakages will heat up the engine components and finally destroy the engine.
I had created the idea to treat the beads of steel gaskets with LASER energy to avoid cracking of the beads and to prolong lifetime of metal cylinder head gaskets. This treatment is very evident for the lifetime of engines and also for the opportunity of designing engines with even more power, running at higher temperatures and lower fuel consumption.
This new idea of mine has also been documented in a patent application at the German Patent Office, published 01. October 1997, No. DE 197 08 970 A1 and at European Patent Office, published 09. September 1998, No. EP 0 863 335 A2. [1]
Until today there is no other patent applied or published regarding the Laser heat treatment at beaded metal cylinderhead gaskets.
This dissertation is describing a method of heat treatment with Laser beam for prolonging life time of beads and finally gives recommendations for improvements on existing gasket concepts.

Preface
Some explanation is reqired to be given. Why, as a German, did I apply this dissertation for doctorate at the MISIS Institute of Technical University of Moscow?
This document has been initiated during a common project between the MISIS-lnstitute (Moscow Institute of Steel and Alloys — Technical University) and the Research and Development Institute of REINZ-Dichtungs GmbH at Neu-Ulm Germany.
I have been manager of the R&D Institute of REINZ from 1994 till 1997.
During that period the MISIS Institute had to develop a FEA calculation method for the material stress analysis of the forming process for preformed (beaded) cylinder head gaskets. The project covered the scientific analysis of the forming processes as well as the analysis of the stresses and the material flow during the forming processes.
In a further project the MISIS institute also was elaborating an advanced calculation method for the determination of the material stresses in sandwich multilayer metal cylinder head gaskets made out of rubber coated (coating thickness from 5pm to 50pm) steel layers whereas the layers could be made out of 0.12 mm to 1,20 mm hard stainless steel. Never before this challenge has been mastered. But the scientists of the teams of Professor Dr. Yuri Vekilov and Professor Dr. Vyacheslav Brinza could work out new methods and an accurate and close to reality stress analysis for the gasket beads when beads are formed during the production process and during the application in an engine.
At that time I had started investigating in lifetime analysis on dynamic fatigue test simulators for finding ways of improvement for multilayer steel gaskets. It turned out material selection and material treatment being of high importance to life time of the products.

[6], [35]. These steel sheets are cold rolled and strain hardened. Later the influence of cold rolling on the material 1.4310 will be explained in more details. The Cr-Ni-steel is heat resistent up to 300° C. No structure change occures from -30° C to 300° C.
Code- Name Chemical Analysis

C% si s% Mn <% Ps% S<% Cr% Ni % Others %
1.4310 X12 CrNi 17 7 <0,12 1,5 2 0,045 0,015 16-18 6-9 Mo<0,
1.4512 X6 CrTi 12 <0,08 1 1 0,04 0,015 10,5-12,5 — Tfe6x%C <1,
1.0330 St2 LG(K60)AI S0.1 0,03- 0,2- 0,06 0,05 — —
0,2 0,
1,4303 X5 CrNi 18 12 <0,07 1 2 0,045 0,03 17-19
4.3 The bead design influencing bead characteristics
For our investigation to show evidence of LASER treatment, we have to focus on single bead behaviour.
The beading process, especially material hardening of the bead, is mainly influenced by the following parameters:
• Material and surface roughness of the male and female part of the tool
• Radius of forming edges of tool
• Dimensions, tolerances/width of female and male forming section
• Targeted bead height
• Deformation speed
• Lubrification and friction between tool and work piece
The graphs below [3] demonstrate compressibility and recovery depending on
- bead design like 'full bead' vs 'half bead' bead hight like '0,30 mm' vs '0,40mm'
- bead width