DE2843110A1 - WELD-ON ALLOY - Google Patents

Description

Patent Attorneys Dipl.-Ing. C U rt Wal I ach

Dipl.-Ing. Günther Koch

Dipl.-Phys. Dr Tino Haibach

Dipl.-Ing. Rainer Feldkamp

D-8000 Munich 2 ■ Kaufingerstraße 8 · Telephone (0 89) 24 02 75 · Telex 5 29 513 wakai d

Date: j ,. October I978

Our reference: 16 375 - K / Yes

APPLICANT: Rolls-Royce Ltd., London / England

SUBJECT: Weld-on alloy

PRIORITY: Great Britain, 4th October 1977

No.41137 / 77

9098U / 1091

The invention relates to weld-on alloys for nickel alloys and to methods of deposition.

Nickel alloys are widely used in the manufacture of parts that are subject to high frictional contact and wear out as a result. However, such alloys have only a low resistance against frictional wear. As a result, they are provided with a thin layer of a weld-on alloy, whose wear resistance characteristics are more in line with these operating conditions.

Two such weldments are cobalt alloys, those under the trade name "STELLITE 12 SP" and "STELLITE 12".

Nickel alloy workpieces bearing layers of "STELLITE 12" or "STELLITE 12SF" actually show wear resistance greater than that of the base alloy so that the life of the workpieces is extended. However, certain properties peculiar to the known weld-on alloys have a realization of at least one significant portion of the available frictional wear resistance potential prevented.

The invention is therefore based on the object of creating a cobalt weld-on alloy that has a larger one Share of the available wear resistance realized than was previously possible. The invention aims further to provide a method for applying the novel weld-on alloy to a nickel alloy, thereby creating a greater wear resistance potential is achieved during operation on a workpiece made from the base alloy consists.

9 0 9.8 U / 1 0 9 1

The invention provides a nickel-free weld-on alloy which contains the following components by weight:

Co $ 50-60

Cr $ 5-35

W 0-1QSi

C $ 0-2.5

Si 0-10 $, where if Si = O some B is present,

B 0-3.5 $, where when B = O some Si is present.

Remainder impurities.

The following percentages of weight are preferably used:

Co $ 52 Cr $ 31 W. $ 8 C. $ 1.4 Si $ 4.5 B. $ 2.9 rest Impurities.

The alloy can be produced in powder form.

The particle size of the powder is then preferably in a range between 45 and 10 5 μm .

The invention also relates to a method for applying the weld-on alloy to a workpiece a nickel alloy. According to the invention, a flexible tape is made by placing the weld-on alloy in powder form is suspended in a binder consisting of polymerization material and by drying the binder by its solvent is allowed to evaporate, whereafter the tape is applied to a surface of a nickel alloy workpiece

9098U / 1091

is applied and this structure in a vacuum to a temperature between 10 and 25 ° C above the liquidus line the weld-on alloy is heated for 15 minutes.

Preheating of the assembly is preferably carried out at about 500 ° C. for 30 minutes in order to avoid vigorous Avoid evaporation of the binder.

The manufacture of a strip from the alloy according to the invention and the manner of treatment for the manufacture of a hard surface layer on a workpiece made of a nickel alloy is described below on the basis of exemplary embodiments described:

There were initially four basic substances in powder form thereby obtained that the ingredients listed in Table 1 were mixed in the specified proportions.

Table 1

alloy Nomine]
of the AlU Cr .le composition
'Welding powder C. Ni Mon Si B. Particle size A. Co 29 W. 1.8 - - - - -250 + 300 B. 59 19th 9 1.0 13th - 2.5 13th -250 + 300 C. 5 31 9 1.4 - - 4.5 2.9 -140 + 325 D. 52 8th 8 = - - 28 2.0 - -325 62 -

In all tables, the hard weld alloys encompassed by the invention are indicated by "C", "/ C" and "C / D" while the remaining alloys A, B and D are commercially available products.

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The solidus and liquidus values for each of these alloys were determined and the result is in Table 2 listed.

Table 2.

alloy Solidus Liquidus A.
B.
C.
D. 128O ° C
1065 ° C
1065 ⁰ O
1230 ⁰ C 1315 ^O C
1145 ° C
1090 ⁰ C
1590 ⁰ C

Table 2 clearly shows that alloy "C" with alloy "B" has the lowest solidus value and had the lowest liquidus value of all alloys. This is a direct result of the inclusion of Si and B.

Alloys of A and C or C and D were also made to determine whether the characteristics of alloy C in such a mixture can be introduced.

Flexible tapes were made as follows: Each powder was placed in a respective solution, the a suitable acrylic resin binder of the type polymethyl methacrylate. This binder choice was made because of this one resulted in sufficient flexibility and also leaves no residue when a pyrolysis in an inert Atmosphere takes place. Drying of the physical-making solution for the tapes was accomplished by evaporation of the solvent achieved.

9098U / 1091

Sections of each tape were then cut and placed on the respective nickel alloy workpieces, and they were attached to these workpieces by means of a pressure acting adhesive. Then the assembly was heated and long initially for half an hour at 5OO ° C in order to avoid a too violent evaporation of the binder and then I5 minutes at a temperature that fluctuated between 11OO ° C and 1190 ⁰ C, as from Fig. Can be seen in order to achieve a hard soldering of the surface layer on the base body. The letters "DNB" mean "no hard soldering took place".

Table 3.

LegJarung - Brazing
temp.
ra Result Nom. Band
thickness Thickness of the
Filing
tion percent
Thick
loss 4th hardness
(Reason-
alloy
tion
383 VPN ■ '- ■' - "- now. 1075 DNB - - - - 1100 DNB - - - - B. 1125 DNB - - - - 1150 Hard
solder 0.82 0.61 25th 513 1175 - - - - ■ 1190 Hard
solder 0.71 0.69 446

9098U / 1091

■ 'ί

Table J5 continued

Legie
tion Hard
lot- ■ «
temp.
Γ ^ J - Er- ν
result Nom.
tape
thickness Thickness of the
Storage University percent
Thick
loss 42 - 35 - hardness
(Basic
yaw
383 VPN) 746 - C. 1075 DNB - - - - 42 - - 658 - α / ο 1100 Hartver
solder 0.74 0.43 51 50 - 552 - CD 1125 Hartver
solder 42 547 1150 Hartver
solder 0.74 0.38 46 509 1175 Hartver
solder 0.79 0.46 - 1190 Hardver.
solder 0.77 0.25 - 1075 DNB - - 1100 DNB . - - 647 1125 DNB - - 639 1150 Hard ver
solder 0.86 0.56 621 1175 Hard ver
solder 0.86 0.50 1190 ' Hard ver
solder 0.86 0.43 1075 DNB - 1100 DNB - 1125 DNB - -

909814/1091

Continuation of table 3

Legie
tion Brazing
terap,
L ^ 7 He
result Nora.
tape
thickness Thickness d.
Filing
tion percent
Thick
loss hardness
(Basic
yaw
383 VPN) 1150 DNB - CD
-.-Ί II75 Hard 0.71 0.41 42 596 II90 Hartver
solder 0.69 0.43 39 563

After studying Table 3, some points become very clear, e.g .:

a) Alloy C allows hard soldering or welding over a very wide temperature range than the other alloys,

b) Alloy C conducts more than only in the lower edge area

the alloys A / C and C / D in terms of loss of deposit thickness,

c) all alloys show higher hardness values when applying the respective lower brazing temperatures,

d) Alloy C shows a considerable improvement in hardness value even compared to the closest one Alloy, i.e. alloy A / C,

e) the alloy C provides at Hartauflötung to a nickel alloy at a temperature of 1100 ⁰ C for 15 minutes a surface whose hardness is harder to about 95 $ than that of the base alloy.

Tables 4 and 5 show the composition of the weld-on

9098U / 1091

/H

alloys B and C after heating for the purpose of Brazing and a comparison of these compositions with conventional ones. The tables also repeat the hardness values after brazing at given temperatures.

Table 4.

Legie Brazing
temp ⁰ C Composition % Co Cr W. Si Ni C. B. ■ hardness
VPN tion 1190
II50 41.6
49.9 17.8
20.3 COO VO
VO O 2.5
2.6 21.7 (-
12.7 j - - ^; 446
t
- j 513
f B. Nominally 52.0 19.0 9.0 2.5 13, Oil, O. 1.5

Time at the respective temperature 15 minutes, Carbon and boron could not be detected by

Table 5.

Legie
tion Brazing
temp. ° C Composition % CO Cr W. Si Ni C. B. hardness
VPN C. II90
II50
1100 23.3
35.2
42.3 8.0
33.0
30.7 9.6
1OA
10.6 2.4
3.0
4.6 2.8
10.8
2.8 509
552
746 Nomi
nell 52.0 31 P. 8.0 4.5 0 1.4 3.0

Time at the respective temperature 15 minutes, Carbon and boron could not be detected by MPA.

9098U / 1091

Table 4 clearly shows that when the brazing temperatures are increased, nickel diffuses from the base body into the weld-on layer. In the present case ergab.sich an increase of about 90 $ of the nickel content when a brazing was carried out at 1190 ⁰ C. There was also a decrease in hardness value by

Table 5 also clearly shows that when alloy C, which initially does not contain nickel, is heated, on a higher brazing temperature results in the transfer of an amount of nickel, a transfer to 28W. $ the overall composition of alloy C. This dramatic increase in nickel content is equally dramatic Accompanying a decrease in the hardness value and, as a result, there is a lower wear resistance.

The weld-on alloys A / C and C / D follow this through Alloy C set trend as far as they are nickel-free alloys and they show an increase in hardness of about $ 20 versus alloy B when brazed was carried out with a workpiece at temperatures high enough to ensure hard soldering and at the same time were so low that substantial transfer of nickel from the workpiece was prevented after application,

The teachings of the invention are as follows:

a) The use of a nickel-free cobalt alloy as a weld-on alloy,

b) heating the base workpiece and the alloy to a temperature above the liquidus line of the alloy (Table 3), but this temperature is close to

90 9814/1091

this liquidus line lies by at least substantially avoid transfer of nickel from the base workpiece to the alloy so that:

c) an application layer is achieved on the basic workpiece, whose hardness value is about $ 95 higher than the hardness value of the base metal piece and up to $ 50 greater than this was the case with known cobalt alloys that

previously used as weld-on alloys. This increase in hardness brings about a considerable improvement the wear resistance of the weld-on or braze alloy.

9098U / 1 091

Claims (7)

Pacer-tanwäiie Dipl.-lng. Cu rt Wal Iach Dipl.-lng. Günther Koch 28431 1 Q Dipl.-Phys. Dr Tino Haibach Dipl.-Ing. Rainer Feldkamp D-8000 Munich 2 · Kaufingerstraße 8 · Telephone (0 89) 24 02 75 · Telex 5 29 513 wakai d Date: October 3, 1978 Our reference: 16 375 - K / Ja -X- patent claims 1) Nickel-free weld-on alloy, characterized in that it contains the following components in wt. having: Co $ 50-60 CR 5-35 ^ W $ 0-10 C $ 0-25 Si 0-10 $, where if Si = O some B is present, B 0-3.5 $ where if B = O some Si is present. Remainder impurities. 2) Nickel-free weld-on alloy according to claim 1, characterized in that the proportions in wt. $ As the following are: Co $ 52 Cr $ 31 W $ 8 C $ 1.4 Si $ 4.5 B $ 2.9 Remainder impurities. 3) Nickel-free weld-on alloy according to claim 1, characterized 9Ö98H / 1091 characterized in that the alloy is reduced to a powder. 4) Nickel-free weld-on alloy according to claim 3, characterized in that the particle size of the powder is at least 45 / jra and at most 105 μm . 5) Nickel-free weld-on alloy according to claim 3, characterized characterized in that the alloy is provided in the form of a flexible tape, which in this form is held by a polymer binder, the solvent content of which has evaporated. 6) Nickel-free weld-on alloy according to claim 5 * thereby characterized in that it is deposited on the surface of a workpiece made of a nickel alloy thereby is that the tape is deposited on the surface and that then heating in a vacuum to a temperature takes place, which is 10 ° C to 25 ° C above the liquidus line of the weld-on alloy and that the heat treatment Continued for 15 minutes. 7) Nickel-free weld-on alloy according to claim 6, characterized in that the workpiece with the band arranged thereon is ^{heated to about 500 0} C JO minutes before the temperature is raised to 10 C to 20 ° C above the liquidus line of the weld-on alloy. 909814/1091