U.S. patent application number 12/305526 was filed with the patent office on 2009-12-03 for heat-resistant bearing material.
Invention is credited to Roland Ruch, Lutz Steinert, Klaus Wintrich.
Application Number | 20090298726 12/305526 |
Document ID | / |
Family ID | 38288937 |
Filed Date | 2009-12-03 |
United States Patent
Application |
20090298726 |
Kind Code |
A1 |
Ruch; Roland ; et
al. |
December 3, 2009 |
HEAT-RESISTANT BEARING MATERIAL
Abstract
A heat-resistant bearing material consisting of an austenitic
iron matrix alloy should, under high temperatures, have good solid
lubricant properties with a high heat resistance and a high creep
resistance. To this end, an iron matrix alloy is used, containing a
sufficient sulphur part for obtaining a solid lubricant action on
the bearing surfaces thereof, and between 1 and 6 wt. % of at least
one of the following alloy elements: tungsten (W), cobalt (Co),
niobium (Nb), rhenium (Re), molybdenum (Mo), tantalium (Ta),
vanadium (V), hafnium (Hf), yttrium (Y), zirconium (Zr), and/or
comparably high-melting alloy elements.
Inventors: |
Ruch; Roland; (Schopfheim,
DE) ; Steinert; Lutz; (Schopfheim, DE) ;
Wintrich; Klaus; (Schopfheim, DE) |
Correspondence
Address: |
RADER, FISHMAN & GRAUER PLLC
39533 WOODWARD AVENUE, SUITE 140
BLOOMFIELD HILLS
MI
48304-0610
US
|
Family ID: |
38288937 |
Appl. No.: |
12/305526 |
Filed: |
May 31, 2007 |
PCT Filed: |
May 31, 2007 |
PCT NO: |
PCT/EP2007/055312 |
371 Date: |
May 26, 2009 |
Current U.S.
Class: |
508/152 |
Current CPC
Class: |
F16C 33/121 20130101;
C22C 38/02 20130101; C22C 38/44 20130101; C22C 38/60 20130101; F16C
2300/54 20130101; C22C 38/48 20130101; F16C 2360/00 20130101; F16C
2204/64 20130101 |
Class at
Publication: |
508/152 |
International
Class: |
C10M 125/06 20060101
C10M125/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 22, 2006 |
DE |
10 2006 029 121.2 |
Claims
1. A heat-resistant bearing material that is an austenitic iron
matrix alloy, consisting of: a sufficient sulfur percentage to
achieve a solid lubricant action on bearing surfaces of the bearing
material, and between 1% w/w and 6% w/w of at least one or more of
the melting alloy elements: tungsten (W), cobalt (Co), niobium
(Nb), rhenium (Re), molybdenum (Mo), tantalum (Ta), vanadium (V),
hafnium (Hf), yttrium (Y), zirconium (Zr) and an alloy with a
comparable melting point to the melting alloy elements; and wherein
the following alloy composition is included, where the individual
alloy elements are each indicated in % w/w: C=0.4-0.6 Cr=18-27
Nb=1.4-1.8 Ni=12-22 S=0.2-0.5 Si=2.9-3.2 Residue=Iron Contaminants
or unspecified alloy elements up to 3.
2. The bearing material according to claim 1, wherein the following
alloy composition is included, where the individual alloy elements
are each indicated in % w/w: C=0.4-0.6 Cr =18.5-20.5 Nb =1.4-1.8 Ni
=12.5-14 S =0.25-0.45 Si=2.9-3.15 Residue=Iron Contaminants or
unspecified alloy elements up to 3.
3. The bearing material according to claim 1, wherein the following
alloy composition is included, where the individual alloy elements
are each indicated in % w/w: C=0.4-0.6 Cr=24.5-26.5 Nb=1.4-1.8
Ni=19.5-21.5 S=0.25-0.45 Si=2.9-3.15 Residue=Iron Contaminants or
unspecified alloy elements up to 3.
4. The bearing material of claim 1, wherein a paddle bearing ring
is constructed of the bearing material.
Description
[0001] The invention relates to a heat-resistant bearing material
consisting of an austenitic iron matrix alloy, and here addresses
the problem of making such a bearing material functionally reliable
for use at high temperatures, especially at temperatures exceeding
600.degree. C., in particular exceeding 850.degree. C. The bearing
material here is to exhibit solid lubricant properties, which are
to be retained at the specified high temperatures to as high a
degree as possible.
[0002] This object is achieved by means of a bearing material
according to the characterizing features of claim 1
[0003] Advantageous alloys of such a bearing material are the
subject matter of the subclaims.
[0004] The invention is based on the general idea of providing
sulfur in a percentage amount that allows sulfides required for a
lubricating effect to form within the alloy. Such a formation of
sulfide within an austenitic matrix alloy intended to exhibit a
high creep resistance and high strength at high temperatures is a
contradiction in and of itself. This contradiction stems from the
fact that, based on general expert knowledge, sulfides contained in
such a material are disadvantageous for a high creep resistance and
high strength at high temperatures because they constitute a
structural disturbance, and must therefore be avoided. Therefore,
the invention proposes something that runs absolutely counter to
general expert knowledge with respect to the objective of obtaining
a material that is highly creep resistant and strong in terms of
temperature, and still exhibits lubricating properties even at high
temperatures, and hence represents a surprising result not to be
expected by an expert.
[0005] The drawing shows a few diagrams depicting characteristics
for bearing materials according to the invention. The curves
denoted in individual diagrams relate to a material according to
claim 7 if marked A, and a material according to claim 8 if marked
B.
EXPLANATION TO INDIVIDUAL DIAGRAMS
[0006] FIG. 1a, 1b
[0007] These diagrams show the creep behavior of alloys A and B
during the gradual exposure of a sample in increments of 2 MPa, a
retention period of 35 sec and when measuring the creep rate in the
last 5 sec of the retention period, specifically in part a for a
creep behavior at 700.degree. C., and in part b for a creep
behavior at 900.degree. C.
[0008] FIG. 2
[0009] This diagram records the modulus of elasticity E and sheer
modulus G for alloys A and B as a function of temperature.
[0010] FIG. 3
[0011] This diagram depicts the thermal expansion coefficient for
alloys A and B as a function of temperature.
[0012] FIG. 4
[0013] This diagram records the hot hardness (in HV10) on the
ordinate as a function of the temperature for alloys A and B.
[0014] FIG. 5
[0015] The ordinate shows the hardness (in HB 2.5/187.5) for alloys
A and B after stored for a respective 2 hours and air-cooled as a
function of temperature.
[0016] FIG. 6
[0017] This figure contains a table that indicates values for p
=density, .lamda.=heat conductivity, R.sub.p02=expansion limit,
R.sub.m=tensile strength, E=modulus of elasticity for alloys A and
B at respective room temperature.
[0018] All features described in the specification and the
following claims can be significant to the invention both
individually and taken together in whatever form.
* * * * *