FR2482627A1 - EROSION RESISTANT METAL ALLOY - Google Patents

Abstract

EROSION RESISTANT SURFACE HARDENING ALLOY. IT IS ESSENTIALLY COMPOSED OF TITANIUM CARBIDE AND AN APPROPRIATE MATRIX. THE MATRIX IS AN ALLOY BASED ON IRON, COBALT OR NICKEL. THE TITANIUM CARBIDE WEIGHT CONCENTRATION IS BETWEEN APPROXIMATELY 5 AND 60.

Description

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  The invention relates to surface hardening alloys and more particularly to an alloy having a high erosion resistance. Manganese steel composed of approximately 12% o manganese, 1%> carbon and iron for the complement is usually used when a hardening treatment is permitted as desired. Originally, manganese steel has a hardness of about 88 to 92 Rb which is increased after curing treatment to about

50 to 5. ' iec.

  While manganese steel has sufficient resistance

  with various types of wear such as abrasive wear, adhesion wear including excoriation, it lacks

  resistance to erosion wear, especially before treatment

  hardening. It has been found that even the well-known nickel hardened hardening alloys

  lack of resistance to erosion wear.

  For experimental purposes, a well-known nickel-based alloy, surface hardening, composed of approximately

  0.5% carbon, 2.2% boron, 13.5% chromium, 3.5% silicon,

  and the iron complement, where the balance is 100% nickel, is

  deposited on a manganese steel substrate using

  transferred to plasma transfer arc. For this experiment, the Linde plasma transfer arc installation is implemented with a current of 200 amps and a voltage of

  volts to deposit a coating layer of 3e2mm of

  thickness of the alloy hardening surface on a piece

  manganese steel 50mm x 50mm x 25mm.

  The surface of the hardened nickel alloy

  The face is subjected to erosion wear by throwing hardened iron grains on it at a relative pressure of 7000 N / m2 for 4 minutes, and the weight loss due to erosion wear is compared to the loss. weight of a manganese steel reference specimen subjected to the same erosion wear. Surprisingly, the alloy

  hardened nickel base in the surface loses 4.5g then the bare

  The reference value in old manganese loses only 2.8 g.

  The present invention provides hard-wearing alloys

  new and useful surface cements with high erosion resistance compared to manganese steel

  and known surface hardening alloys.

  According to the invention, erosion-resistant surface-hardening alloys suitable for the

  plasma transfer arc and other applications, are

  characterized in that they essentially comprise a carbide of

  titanium in a suitable matrix.

  According to the invention, it has been found that an alloy consisting essentially of about 10 to 25% by weight of titanium carbide in a suitable matrix, preferably based on iron, has a high resistance to erosion, low porosity and lack of crack, as shown by

the following tests.

  Four test pieces made of different materials are used.

  Specimen No. 1 is a mango steel plate.

  ordinary nese composed by weight of about 12% of manganese, 1%

carbon, the rest being iron.

  Sample No. 2 is an alloy composed by weight of% of titanium carbide, 7% of nickel and 78% of an iron-based matrix composed by weight of sensitively 29% of chromium, 2.5% of carbon the rest being iron. This material is deposited on a 50mm x 50mm x 25mm manganese steel substrate

  thanks to the plasma transfer arc process, the layer de-

  placed approximately 3mm thick.

  The test n03 is composed essentially of

  approximately 50% by weight of tungsten carbide and 50% by

  nickel-based compound composed by weight of approximately 14%

  chromium, 3% boron, 4% silicon, the balance being nickel.

  The test piece n04 is composed essentially by weight of approximately 20% of titanium carbide, 7% of nickel and 73%

316 stainless steel.

  The materials of the specimens 3 and 4 are deposited on a manganese steel substrate by the same process as

  the one used for specimen n02.

  All four specimens are subjected to various tests including erosion wear, abrasive wear and

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  hardness. The erosion test consists of projecting

  cast iron (iron no. 16) dipped under a different pressure

  7,000 iN / m2 on the surface of the specimen for 4 minutes and note the weight loss of three samples of each type of specimen. The results

following are obtained.

  WEAR TEST EROSION Test specimen N 1 2 3 4 Weight loss (grams) 2.7 0.10 392 290

2.6 0.20 3.8 1.8

391 0917 - 199

  Average weight loss 2.8 0915 395 1.9 Titanium carbide alloy in a base matrix

  iron appears to be clearly superior to other materials.

  The abrasion test consists in grinding the test piece by rotating it against a stationary steel disc, in a container in which a mixture of

  cm3 of water and 50g of abrasive grains (140 mesh) of

  Silicon bure. The specimens are attached to a drill press weighing 2,250 kg with a 15 cm lever arm. The test specimen rotates at 250 rpm for 15 minutes. The weight loss of the test piece is

then determined.

  TEST OF WEAR ABRASION Test tube NO 1 2 3 4 Weight loss (grams) 1.37 0924 193 0959

1944 0914 1.2 0960 '

  The abrasion wear test demonstrates that the titanium carbide alloy in an iron-based matrix is significantly superior.

  The hardness of each test piece is also determined

  born according to ASTM E-78-14, VOL. 10-1975. The average value of five tests carried out on each of the samples is given below: Test specimen N 1 2 3 4 hardness (Rockwell) Rb9O Rc52 ltc52 Rc32 It is noted that there is no loss of hardness of the

  compared to the 50% tungsten carbide test piece.

  In order to determine the optimal concentration of tungsten carbide in the iron matrix, the hardness was determined for several compositions. The results are as follows: COMPOSITION IN WEIGHT% HARDNESS (Rockwell) A. 10% TiC + 12% Ni + 78% Fe-Cr-C Rc 48 B. 15% TiC + 5% Ni + 80% / Fe-Cr C Rc 51.5 C. 25% TiC + 7% Ni + 68% Fe-Cr-C Rc 54 D. 35% TiC + 10% Ni + 55% Fe-Cr-C not measurable E. 45% TiC + 12 % Ni + 43% Fe-CrC not measurable The deposits of alloys containing 35% o and 45% o by weight of titanium carbide have cracks and are not

tested.

  On the basis of all the observable data re-

  Following tests, an alloy composed essentially of

  from approximately 5% to 25% of titanium carbide, approximately

  5% nickel, and the rest being a matrix of

  iron-based alloy consisting essentially of weight of

  approximately 29% o of chromium, 2.8% of carbon, 0.1% of man-

  gansis, 0.8% silicon, the balance being iron,

  increased erosion compared to art

  previous, without sacrificing other qualities.

  Beyond the chemical composition of the titanium carbide alloy described above, it has been found that the particle size of the titanium carbide should preferably be 270 mesh or less, and still more preferably than

  particle average is between 10 and 20 microns.

  For particle sizes more'grandesily has a slight

  loss of resistance to erosion wear, and for

  particles, the effectiveness of the deposit is lost and a slight oxidation of

titanium carbide.

  In addition, it has been found that optimal results are obtained if the nickel has a particle size smaller than

  meshetsila matrix based on iron has a particle size ind

  less than 60 mesh and greater than 325 mesh. If the matrix has a particle size greater than 60 mesh, it does not circulate well in nozzle nozzles of customary dimensions. Well

  sdr, this is not a problem if you do not use the

  transferred to plasma transfer arc. If the matrix powder has a

  particle size less than 325 mesh, the oxidation of

  cules of the matrix tends to appear. Again, if the plasma transfer arc process is not used, the smallest particle size is not a problem.

  Although the tests are carried out for depotsapplied

  by plasma transfer arc, any melting facility may be used, including welding

  autogenous, the tungsten welding under inert gas and the

  In addition to the above tests on titanium carbide alloys employing an iron-based matrix, nickel-based and cobalt-based matrices also have

  high resistance to erosion wear.

  A series of comparative tests are performed on cobalt-based and nickel-based matrices compared to each other, and iron-based matrices without the use of

  additional nickel, as shown above.

  Titanium carbide weight centers, from 5% up to 60%, with the remainder being the matrix, are ossayed. Each test alloy is deposited in the form of a flat layer.

  at a substantially uniform thickness of 3mm over a

  50mm x 50mm x 25mm steel 1020 as a substrate using the Linde arc transfer system

  plasma, model No. PT-9-H.D., with a current of 200 amperes.

  under a voltage of 30 volts. Each specimen is bombarded with cast iron grains (No. 16) dipped at a differential pressure of 7000 N / m 2 for 4 minutes, and the erosion weight loss is determined. The compositions of the matrices are as follows: Base Fe Base Co Base Or

C 0.12 1.2 1.9

  Cr 13.00 29.0 27.0 Mn 0.50 1.0 0.15 If 1.00 1.0 1.50 Fe remains 3.0 10.00

W - 4.5 5.20

  Ni - 3.0 remains Co - remainder 9.0 The matrices have a mesh size smaller than and greater than 325 mesh. Titanium carbide has a

  particle size less than 270 mesh (15 to 20 microns).

  The hardness of each test piece is determined by means of

  a standard test bench for Rockwell hardness.

  For these series of tests, the matrices are allo-

  known to harden surface. The results of the swarms as reported above show that the addition of

  titanium carbide to known hardening alloys

  face greatly increases hardness and strength

  to wear by erosion of the matrix.

RESULT OF TESTS

  TiC in a cobalt-based matrix Dep8t Loss of weight (g) Hardness of the deposit Matrix 3.2 Rc 37 5% TiC + 95% Matrix 1.8 Re 49% TiC + 85% Matrix 1, 0 ce 52% TiC + 75% Matrix 0.8 Rc 58% TiC + 65% Matrix 0.8 -Re 62% TiC + 55% Matrix 0.4 Rc 64 60% o TiC + 40% Matrix 0.1 Rc 65 TiC in a matrix based on iron Deposit Weight loss () Depth hardness Matrix 2.8 Rc 26% TiC + 95% Matrix 2.1 Re 34 15% TiC + 85% o Matrix 1.5 Rc 43% TiC + 75% Matrix 0.9 Rc 64% TiC + 65% Matrix 0.7 Rc 68% TiC + 55% Matrix 0.3 Rc 69% o TiC + 40% Matrix 0.4 Rc 66 TiC in a nickel-based matrix Dept Weight loss (g) Hardness deposition Matrix 4.6 Rc 31% TiC + 95% Matrix 4.6 Rc 32 15% TiC + 85% o Matrix 4.4 Rc 34% o TiC + 75% Matrix 4.3 Rc 45% TiC + 65% o Matrix 4.1 Rc 50% TiC + 55% o Matrix 2.9 Rc 56% TiC + 40% Matrix 2.4 Rc 62 The results of the tests support the following conclusions: 1. The weldability of all powders

  excellent value. The powders "wet" the material well.

  As little as 5% by weight of TiC particles in a matrix causes appreciable differences in the physical properties of the deposit. The hardness of the deposit and the resistance to

  erosion of the deposit are increased.

  3. Deposits comprising 60% by weight of TiC particles do not form crack, indicating that large amounts of carbide can be used to achieve maximum hardness and maximum erosion resistance. 4. Different matrix materials, for example iron-based, cobalt-based or base-based, may be used.

  nickel to obtain a deposit resistant to erosion.

REYENIDICAT IONS

  1. Surface hardening alloy resistant to

  erosion, characterized in that it is essentially

  A titanium carbide and a suitable matrix are used, the titanium carbide concentrations being just sufficient to achieve the desired level of resistance to erosion. 2. Alloy according to claim 1, characterized in

  that the matrix is an iron-based alloy.

  3. Alloy according to claim 1, characterized in

  what the matrix is based on cobalt.

  4. Alloy according to claim 1, characterized in

  the matrix is nickel-based.

  5. Alloy according to any one of the claims

  1 to 4, characterized in that the concentration by weight of titanium carbide is between approximately 5 and%.

  An alloy according to any of the claims

  1 to 4, characterized in that the particle size of the carbide of

  Titanium is equal to or less than approximately 270 mesh.

  7. Alloy according to any one of the claims

  1b 4, characterized in that the particle size of the material constituting the matrix is less than approximately mesh, and is greater than approximately 325 mesh,

  8. Alloy according to any one of the claims

  1 to 4, characterized in that the concentration of the titanium carbide is between about 5% and about%, and that the particle size of the titanium carbide is

less than about 270 mesh.

  9. Alloy according to any one of the claims

  1 to 4, characterized in that the concentration by weight of the titanium carbide is between about 5% and about>, in that the particle size of the titanium carbide is less than about 270 mesh, and that the particle size of the titanium carbide is matrix material is less than about 60 mesh and is greater than 325 mesh environe