U.S. patent application number 16/480517 was filed with the patent office on 2019-12-26 for new product and use thereof.
This patent application is currently assigned to Hoganas AB (Publ). The applicant listed for this patent is Hoganas AB (Publ). Invention is credited to Senad DIZDAR.
Application Number | 20190388964 16/480517 |
Document ID | / |
Family ID | 57909532 |
Filed Date | 2019-12-26 |
United States Patent
Application |
20190388964 |
Kind Code |
A1 |
DIZDAR; Senad |
December 26, 2019 |
NEW PRODUCT AND USE THEREOF
Abstract
The present invention relates to a new pre-alloyed metal based
powder, intended to be used in surface coating of metal parts. The
powder is deposited using e.g. laser cladding or plasma transfer
arc welding (PTA), or thermal spray (e.g. HVOF). The powder is
useful for reducing friction and improving wear reducing properties
of the deposited coating. Such coatings may also improve
machinability. As friction or wear reducing component, inclusions
of manganese sulphide or tungsten sulphide in the pre-alloyed
powder may be used.
Inventors: |
DIZDAR; Senad; (Hoganas,
SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hoganas AB (Publ) |
Hoganas |
|
SE |
|
|
Assignee: |
Hoganas AB (Publ)
Hoganas
SE
|
Family ID: |
57909532 |
Appl. No.: |
16/480517 |
Filed: |
January 26, 2018 |
PCT Filed: |
January 26, 2018 |
PCT NO: |
PCT/EP2018/051935 |
371 Date: |
July 24, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C23C 4/06 20130101; B22F
2301/052 20130101; B22F 2304/15 20130101; B22F 2301/35 20130101;
B22F 2303/20 20130101; B22F 2303/30 20130101; C23C 24/103 20130101;
B22F 2302/40 20130101; C23C 4/134 20160101; B22F 2304/058 20130101;
B22F 1/0011 20130101; C23C 4/067 20160101; C22C 19/05 20130101 |
International
Class: |
B22F 1/00 20060101
B22F001/00; C23C 4/067 20060101 C23C004/067; C23C 4/134 20060101
C23C004/134 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 27, 2017 |
EP |
17153509.9 |
Claims
1. A powder mixture containing: i) atomised metal powder having the
following composition: C, 0.05-0.5%; Si, 2.0-4.0%; B, 0.8-1.3%; Cr,
2-10%; Fe, 3-15%; Al, 0.3-0.5%; Mn, 5-15%; the balance being Ni,
ii) atomised metal powder having the following composition: C,
0.05-0.2%; Si, 2.2-2.9%; B, 0.8-1.3%; Cr, 2.8-3.45%; Fe, 1.4-2.3%;
Al, 0.3-0.5%; S, 3-13%; the balance being Ni, and iii) atomised
metal powder having the following composition: C, 0.2-0.27%; Si,
3.5%; B, 1.6; Fe, 2.5; Cr, 7.5; the balance being Ni.
2. The powder mixture according to claim 1, wherein the ratio
between the powders are such that the amount of MnS is 4-15%.
3. A metal powder according to claim 1, wherein the particle size
of the prealloyed powder is from 45 .mu.m to 200 mm.
4. A method for surface coating metal parts, by way of laser
cladding or PTA (plasma transferred arc), with a metal powder
according to claim 1 thereby producing a metal coated component.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a powder mixture of three
different pre-alloyed metal based powders, intended to be used in
surface coating of metal parts. The powder mixture is deposited
using e.g. laser cladding or plasma transfer arc welding (PTA), or
thermal spray (e.g. HVOF). The powder mixture is useful for
reducing friction and improving wear reducing properties of the
deposited coating. Such coatings may also improve machinability. As
friction or wear reducing component, inclusions of manganese
sulphide or tungsten sulphide in the pre-alloyed powder may be
used.
BACKGROUND
[0002] Thermal surfacing i.e. thermal spray coating and overlay
welding powder grades are widely used for coating of component
surfaces against wear and corrosion. Fe--, Ni-- and Co-- based
grades are known to radically improve life time of wear- and/or
corrosion exposed components. However, there is still a large
number of applications where component life times need to be
improved. In addition, high prices and limited availability of Ni
and Co on the world market also calls for longer life time
improvement. Finally, development of new coating deposition methods
like laser cladding, cold spraying and high velocity spraying open
new possibilities for alloying, more accurate control of coating
process and higher automation, thereby calling for additional types
of powders.
[0003] One approach to improve friction and wear properties may be
to incorporate solid lubricant to thermal surfacing grades so that
the deposited coating includes friction and wear reducing
substances while maintaining acceptable levels of corrosion
resistance and hardness.
[0004] Solid lubricants are soft solid phase materials which are
capable of reducing friction and wear between two surfaces sliding
against each other without the need for a liquid media. Materials
to be considered as solid lubricants need to meet at least the
following criteria: adhere contacting surfaces--stickiness: low
shear strength--low intrinsic friction; low hardness--low
abrasivity and thermochemical stability for the intended
environment. Examples of solid lubricants are; talc, graphite,
manganese sulphide (MnS), molybdenum disulphide (MoS.sub.2), or
tungsten disulphide (WS.sub.2). Use of solid lubricants may provide
advantages in: stability at extremely low or high temperatures;
stability in extreme environments, such as cold or hot
environments, or environments having high radiation levels;
mechanical design issues (lighter design, reduced critical
velocity) or able to carry extreme loads.
[0005] For a long time, the use of solid lubricants in thermal
surfacing has been a difficult proposition, the reason being that
numerous solid lubricants are metal sulphides and that even trace
amounts of sulphur in welds can lead to cracking and/or
corrosion.
[0006] Skarvelis et al; ASME J. Tribol. 132 (2010)
031302-1-031302-8, Surf. & Coat. Techn. 203 (2009) 1384-1394,
and Trib. Int. 42 (2009) 1765-1770 describe the use of mixing MnS
powder with a metal powder and using the resulting powder mix in
e.g. PTA (plasma transferred arc welding).
[0007] An additional example of using metal powder in conjunction
to MnS as solid lubricant is disclosed in Senad et al;
WO2014090922.
[0008] Solid lubricants, however may have high friction coefficient
compared to that of oil or grease; finite wear life for solid
lubricant films when renewal is not possible; no or limited cooling
capacity compared to oil or grease, or tendency to clogging caused
by debris and residual particles.
SUMMARY OF THE INVENTION
[0009] It may be possible to add e.g. manganese and sulfur as
individual components in a metal powder, i.e. as separate powder
particles. These components will then (when the metal powder melts)
form a so-called solid lubricant (in this case MnS). There are,
however, drawbacks of having e.g. Mn and S as individual
components, such as severe dusting, and formation of inhomogenous
inclusions of MnS in the final surface coating.
[0010] The inventor of the present invention has now found that it
may be advantageous to add each of the components of the solid
lubricant to separate metal powders and then mixing the metal
powders either concurrently with carrying out the surface coating
procedure, or prior to carrying out the surface coating procedure.
In short, three powders are mixed; one metal powder containing
manganese or tungsten; one metal powder containing sulfur; and one
iron based powder to enable proper ratios between the various
components. Mn, W, and S are pre-alloyed in their respective powder
particles. These three metal powders are then mixed together and
used in a surface coating procedure, wherein the metal particles
are melted, and MnS or WS inclusions are formed in the melt (also
termed melt pool).
[0011] In the case of MnS, because of MnS formation in the melt
pool, the slag cannot be easily removed from the top of the melt.
The slag is left on the top or sides of the surface coating, such
as an overlay welding seam. If on the sides, the next seam will
cover the slag and the slag will not have time enough to move to
the seam top. Because of this, the microstructure of the resulting
hard face includes both fine-dispersed MnS but also slag-MnS.
[0012] Surprisingly, the inventor has noticed that the powder
mixture according to the present invention can be used in
applications with high tolerance with regard to surface quality
(such as surface finish, slag formation, or dimensional
variability). The resulting hard face is thus suitable for use in
heavy outdoor equipment, such as rails, wheels in rail- and
tram-ways, mining-, agriculture-, oil-, gas-, and
construction-tools.
FIGURES
[0013] FIG. 1 Wear rate vs. sliding velocity for S-powder clad pin
and carbon steel pin for Hertzian max. contact pressure of 500
MPa.
[0014] FIG. 2 Wear rate vs. sliding velocity for S-powder clad pin
and carbon steel pin for Hertzian max. contact pressure of 1000
MPa.
[0015] FIG. 3 SEM micrograph of S-powder clad, top of the
micrograph is wear test surface.
[0016] FIG. 4 SEM micrograph of S-powder clad, top of the
micrograph is wear test surface.
DETAILED DESCRIPTION
[0017] All percentages herein, and in the claims are % by
weight.
[0018] The invention is a powder mixture containing; [0019] i)
atomised metal powder having the following composition; C,
0.05-0.5%; Si, 2.0-4.0%; B, 0.8-1.3%; Cr, 2-10%; Fe, 3-15%; Al,
0.3-0.5%; Mn, 5-15%; the balance being Ni; [0020] ii) atomised
metal powder having the following composition; C, 0.05-0.2%; Si,
2.2-2.9%; B, 0.8-1.3%; Cr, 2.8-3.45%; Fe, 1.4-2.3%; Al, 0.3-0.5%;
S, 3-13%; the balance being Ni; [0021] iii) atomised metal powder
having the following composition; C, 0.2-0.27%; Si, 3.5%; B, 1.6;
Fe, 2.5; Cr, 7.5; the balance being Ni.
[0022] Further, the invention is a powder mixture according to the
above, wherein the ratio between the powders are such that the
amount of MnS is 4-15%.
[0023] Further, the invention is a metal powder according to the
above, wherein the particle size of the prealloyed powder is from
45 .mu.m to 200 mm, or from 50-150 .mu.m.
[0024] The invention is also a method for surface coating metal
parts, by way of laser cladding or PTA (plasma transferred arc),
with a metal powder according to the above, thereby producing a
metal coated component.
[0025] It is previously known that solid lubricants such as MnS or
WS are useful in the field of surface coating, whereby a hard phase
is formed on the surface of a substrate. MnS or WS function as a
so-called solid lubricant. The present inventor has shown that a
mixture of metal powders can be used in a surface coating
procedure, such as plasma transfer arc, and by choosing the right
components in the individual metal powders, the solid lubricant can
form in the resulting surface coating or hard phase. The metal
powders may be nickel, cobalt, or iron based.
[0026] Three atomised metal powders are used in the mixture
according to the invention; In one embodiment, Powder M may have
the following composition; C, 0.05-0.5%; Si, 2.0-4.0%; B, 0.8-1.3%;
Cr, 2-10%; Fe, 3-15%; Al, 0.3-0.5%; Mn, 5-15%; the balance being
Ni. The powder was prepared by atomisation of a melt containing the
elements above in said amounts. The resulting powder contains Mn as
inclusions in a matrix of metal alloy. This powder is herein
denoted "Powder M";
[0027] Powder S may have the following composition; C, 0.05-0.2%;
Si, 2.2-2.9%; B, 0.8-1.3%; Cr, 2.8-3.45%; Fe, 1.4-2.3%; Al,
0.3-0.5%; S, 3-13%; the balance being Ni. The powder was prepared
by atomisation of a melt containing the elements above in said
amounts. The resulting powder contains S as inclusions in a matrix
of metal alloy. This powder is herein denoted "Powder S"; and the
third powder is 1540--a standard grade. This powder is herein
denoted "Powder MP".
[0028] Powder S, Powder Mn and powder P are mixed, in order to
achieve 4-15% MnS in the final melt pool which forms in the below
mentioned cladding methods. This powder mixture is herein denoted
"Mixture PM".
[0029] The Mixture PM is especially well suited for weld cladding
methods, such as laser cladding or PTA. In addition, thermal spray,
e.g. flame spray, HVOF, HVAF, coldspray, plasma spray, and the like
may also be suitable applications.
[0030] The prealloyed nickel, iron, or cobalt based powder is
preferably produced by water or gas atomization of a melt which
includes Mn, W, or S and other alloying elements chosen from the
group consisting of C, Si, B, Cr, Fe, Al, Ni, Co, and V.
[0031] The particle size of the pre-alloyed powder alloy is
typically from 10 .mu.m to 800 .mu.m, or from 10 .mu.m to 200
.mu.m, or preferably from 15-150 .mu.m, or 50-150 .mu.m.
[0032] In one aspect, the invention provides a method for surface
coating metal parts, by way of deposition techniques such as laser
cladding or PTA (plasma transferred arc); thermal spray methods
such as HVOF (high velocity oxy fuel spray), HVAF (high velocity
acetylene fuel spray) or plasma spray; or by slurry methods such as
centrifugal casting, with the above mentioned metal powder.
[0033] In a further aspect, the invention also provides metal parts
produced by the above mentioned suitable for coating by the powder
according to the invention for dry friction contacts in machinery,
such as e.g. industrial valves, sheet metal forming (SMF) tools,
transport rollers in iron works, paper knives, and glass
moulds.
EXAMPLES
Example 1
[0034] Preparation of Pre-alloyed Powder
[0035] A metal powder with the following composition; C, 0.05-0.5%;
Si, 2.0-4.0%; B, 0.8-1.3%; Cr, 2-10%; Fe, 3-15%; Al, 0.3-0.5%; Mn,
5-15%; the balance being Ni, was prepared by atomisation of a melt
containing the elements above in said amounts. The resulting powder
contains Mn as inclusions in a matrix of metal alloy. This powder
is herein denoted "Powder M".
[0036] An additional metal powder with the following composition;
C, 0.05-0.2%; Si, 2.2-2.9%; B, 0.8-1.3%; Cr, 2.8-3.45%; Fe,
1.4-2.3%; Al, 0.3-0.5%; S, 3-13%; the balance being Ni, was
prepared by atomisation of a melt containing the elements above in
said amounts. The resulting powder contains S as inclusions in a
matrix of metal alloy. This powder is herein denoted "Powder
S".
[0037] 1540--a standard grade This powder is herein denoted "Powder
M P".
[0038] Powder S, Powder Mn and powder P are mixed, 3MA powder mix,
in order to achieve 4-15% MnS.
Example 2
[0039] Application of Powder by Deposition using PTA
[0040] Pre-alloyed or pre-mixed powder was applied to test samples
as follows; Powder A was deposited onto S235JRG (base structural
steel) substrate plates by PTA (plasma transfer arc) with
parameters set to allow for a dilution of 5-15%.
Example 3
[0041] Powder S was spread by hand on substrate as a powder before
fusing with the substrate. How was the powder fuwed?
Example 4
[0042] Powder according to the invention was also applied to
substrate by laser cladding. The coating from Powder S appears to
result in finer inclusion sizes of MnS than when applied by
PTA.
Example 5
[0043] Block on ring wear testing was performed, and shows the
beneficial effects of 3MA powder mix in a metal surface coating
layer or clad. The specimens were rectangular blocks
10.times.10.times.50 mm where the base metal was commonly used low
carbon structural steel (EN S235 JRG, ASTM A570 Gr.36) and the
surface layer was at least 0.5 mm thick in the as finished measure.
The test surface had a ground finish with surface roughness of Ra
0.3-0.4 .mu.m, prepared by grinding. The counter rings
o60/R100.times.o20.times.16 mm were made of UIC 900A rail steel.
The test was unlubricated i.e. dry, and the test samples were
carefully cleaned and then degreased by ethanol prior to testing.
The testing was performed as a wear mechanism mapping trial. The
test normal load was 5 and 42 N what correspond 500 respective 1000
MPa in max. Hertzian contact pressure. Sliding velocity was 0.045,
0.13, 0.37, 1.1 and 2.9 m/s. The total sliding distance was 800 m.
Results are shown in FIG. 1 and FIG. 2 for contact pressures of 500
respective 1000 MPa. FIG. 3 and FIG. 4 illustrate microstructure of
S-powder laser clad.
* * * * *