CN1143002A

CN1143002A - Titanium carbide-zirconium carbide-vanadium carbide series high hardness wear-resistance stacking welding rod

Info

Publication number: CN1143002A
Application number: CN 95110589
Authority: CN
Inventors: 邹勇; 邹增大
Original assignee: Shandong Polytechnic University
Current assignee: Shandong Polytechnic University
Priority date: 1995-08-16
Filing date: 1995-08-16
Publication date: 1997-02-19
Anticipated expiration: 2015-08-16
Also published as: CN1059621C

Abstract

The invented built-up welding rod firstly adopts arc metallurgic reaction to form low carbon alloy martensite distributed dispersedly with high hardness TiC, VC and ZrC etc hard particles. The welding state hardness of the welding seam HRc is no less than 60, and the arc is stable, the welding seam forming is good, the preheating is not needed to the welding piece, there are no crack droping block and peeling off produced in continuous multilayer bead welding. It features high hardness, highwearability and high anti-crack property. The invented built-up welding rod is extensively applicable to the making and repairing of wearable elements in the metallurgy, mine, agricultural machine and transportation etc. fields. It has outstanding result to strong wearable piece and impact abrasion resisting piece.

Description

Titanium carbide-zirconium carbide-vanadium carbide series high-hardness wear-resistant surfacing welding electrode

The invention belongs to the technical field of welding, and particularly relates to a high-hardness crack-free wear-resistant surfacing welding electrode containing titanium carbide, zirconium carbide and vanadium carbide.

The existing high-hardness (HRc is more than or equal to 60) wear-resistant surfacing welding electrodes at home and abroad mainly comprise two main types, namely a high-alloy cast iron series surfacing welding electrode, wherein the matrix structure of the high-alloy cast iron series surfacing welding electrode is high-carbon alloy martensite, retained austenite and carbide [ Cr [₇C₃(Ee.M)_xCy]Such as Suэ -90B10 x 5 phi 2 (%: C<3.0, W8.0-14.0, Cr4.0-6.0), Chinese heap 628 (%: C3.5-5.0, Cr20.0-35.0, M_o1.0-6.0, V1.0), daily DFCrA (%: c5.3, cr21.5, nb6.0, V1.8, W3.5), and the second is chinese heap 707, heap 717 (%: c1.5-4.0, W40.0-70.0), the two main types of welding rods mainly depend on high-carbon alloy martensite with high hardness and carbide WC (W) with high hard point₂C)、C_r7C₃And the like to obtain a high-hardness weld. But because the high carbon alloy martensite is hard and brittle, WC and C_r7C₃Isocarbides are orthorhombic and hexagonal in lattice type, respectively, and martensitic (ferritic) phasesBody) body-centered cubic lattices are completely different and have large difference in lattice constant, and hard particles such as chromium carbide, tungsten carbide and the like are embedded or brazed on a martensite matrix, and the high-hardness hardfacing electrode has unsatisfactory wear resistance and poor crack resistance due to the fact that the carbide is hard and brittle, has large granularity, is easy to crack and break and fall off.

In order to reduce and prevent welding cracks and peeling, the conventional high-hardness wear-resistant surfacing welding electrode is characterized in that a workpiece is preheated to 400-600 ℃ before welding, tempered at 600-700 ℃ immediately after welding, slowly cooled and the like in a welding process, and high-temperature preheating and post-heat treatment for reducing welding thermal stress are adopted, so that the surfacing cost is increased, and the labor condition is seriously worsened.

Because the existing high-hardness hardfacing electrode has poor crack resistance, cracks are easily generated during welding, and high-temperature preheating is needed during welding, so that the popularization and the application of a hardfacing process are greatly limited and hindered.

Aiming at the problems of the existing high-hardness hardfacing electrode at home and abroad, the invention develops the high-hardness hardfacing electrode which does not need preheating, does not crack in continuous surfacing, has the welding-state hardness HRc of surfacing metal more than or equal to 60 and has low cost.

The technical key point of the invention is to utilize a martensite matrix with higher toughness and add carbide hard particles with high hardness and strong binding force with the matrix. The method mainly selects low-carbon alloy martensite matrix with high-hardness TIC, VC and ZrC hard particles dispersed and distributed. Because the low-carbon alloy martensite has certain hardness and higher toughness, the TiC, CV and ZrC with high hardness are all cubic lattices on the lattice structure, are the same as ferrite (martensite), and have very close lattice constants. Due to a coherent relationship, TiC, VC, Z_rThe binding force of C and iron is far greater than that of WC and C_r7C₃The binding force with iron, and TiC, VC, ZrC granule is fine and is distributed on the basal body in a dispersion state. In addition, TiC, VC and ZrC have high melting points, become crystal nuclei in the crystallization and solidification process of the welding seam, greatly refine welding seam crystal grains and have high hardness of multiple crystal boundariesChemical pair for improving the metal resistance of welding seamsGrindability plays a very beneficial role.

The invention relates to a titanium carbide-vanadium carbide-zirconium carbide series high-hardness wear-resistant surfacing welding electrode, which comprises the following coating formulations (in percentage by weight): 6-15 parts of graphite, 10-53 parts of artificial rutile, 5-12 parts of titanium dioxide, 3-25 parts of zirconite, 6-15 parts of marble, 2-10 parts of magnesia, 3-8 parts of barium carbonate, 6-15 parts of fluorite, 3-30 parts of Fe-Ti10, 3-15 parts of Fe-V5, 3-3 parts of Fe-B0 and 1-3 parts of solid water glass.

The invention utilizes the ultra-high electric arc temperature of the welding process and the violent and sufficient metallurgical process of the molten drop reaction zone, and graphite, artificial rutile, titanium dioxide and ZrO are added into the coating₂And Fe-Ti, Fe-V and the like are subjected to arc metallurgy reaction to generate TiC, VC and ZrC to enter the welding line. The reaction formula is as follows:

the amount of graphite added into the coating of the surfacing electrode is adjusted, and the carbon content in the matrix is controlled to be less than 0.30% through metallurgical reaction. Under the arc metallurgy reaction, the generated TiC, VC and ZrC enter the welding seam after reacting with the molten pool through the molten drop, so that the welding structure of the welding seam is high-hardness carbides such as TiC, VC and ZrC which are dispersed and distributed on the low-carbon alloy martensite.

When the part of Tic, VC, ZrC and the like generated by the arc metallurgy reaction entersWhen molten slag and molten pool are added, because the melting points of Tic, VC, ZrC and the like are very high and the interfacial tension with molten metal and the molten slag is very high, the surface tension and viscosity of molten drop, molten pool metal and the molten slag are increased rapidly, the weld joint forming is poor, and particularly when more high-melting-point carbides such as Tic and the like generated by metallurgical reaction enter the molten drop and the molten slag, the molten slag and the metal are difficult to separate, so that the welding is difficult to carry out. The invention controls the formula of the coating, utilizes solid water glass, basic oxides such as BaO, MgO, CaO and the like to form slag, and acid oxide TiO₂Etc. formThe low-melting-point composite compound has low surface tension with TiC, ZrC and the like, so that the physical and chemical properties of slag are excellent, slag is easy to remove, the forming is good, electric arc is stable, and slag-removing continuous surfacing can be avoided during multilayer welding, so that the welding process is simplified, the slag covered on a welding seam can generate new metallurgical reaction under the action of the electric arc to generate more TiC, VC, ZrC and the like to be transferred into weld metal, and the hardness of the weld metal is improved by 1-2 compared with the hardness HRc of slag-removing welding.

Example (b): the welding rod core adopts H08A, phi 4.0mm, coating formula (weight percent) graphite 8, artificial rutile 38, titanium dioxide 5, zirconite 8, barium carbonate 2, marble 7, magnesia 3, fluorite 8, Fe-Ti12, Fe-V8 and solid water glass 1. And continuously carrying out multilayer surfacing on a press roll of the crusher without generating cracks, wherein the weld hardness of the molten metal is HRC 62-67.

The titanium carbide-vanadium carbide-zirconium carbide series high-hardness wear-resistant surfacing welding electrode is characterized in that hard points of TiC, ZrC, VC and the like with high hardness and strong bonding force with a matrix are dispersedly distributed on the matrix of low-carbon alloy martensite, and has high hardness, high wear resistance and extremely high crack resistance. During overlaying, the electric arc is stable, the weld joint is well formed, high-temperature preheating treatment of workpieces before welding is omitted, continuous multilayer overlaying can be performed, and the weld joint does not generate cracks, blocks and peeling. The cost of the electrode is about 1/3 for the stack 707 of electrodes. The invention thoroughly solves the technical problems that the prior high-hardness hardfacing electrode has unsatisfactory wear resistance, poor crack resistance, and the weldment before welding needs high-temperature preheating treatment for a long time, and the like, can be widely used for manufacturing and repairing wear-resistant parts in the industrial fields of metallurgy, mines, agricultural machinery, petrochemical machinery, transportation and the like, and has remarkable economic benefit and social benefit.

Claims

1. A high-hardness wear-resistant surfacing electrode is characterized in that a coating of the surfacing electrode comprises, by weight, 6-15 parts of graphite, 10-53 parts of artificial rutile, 5-12 parts of titanium dioxide, 3-25 parts of zirconite, 6-15 parts of marble, 3-8 parts of barium carbonate, 2-10 parts of magnesite, 6-15 parts of fluorite, 10-30 parts of Fe-Ti, 10-15 parts of Fe-V5, 0-3 parts of Fe-B and 1-3 parts of solid water glass.

2. The high hardness hardfacing electrode of claim 1, wherein graphite, synthetic rutile, titanium dioxide, ZrO are added to the coating₂And Fe-Ti, Fe-V and the like are subjected to arc metallurgy reaction to generate TiC, VC and ZrC.

3. The high-hardness hardfacing electrode according to claim 1, characterized in that the welding structure of the electrode is carbide hard particles of high-hardness TiC, VC, ZrC, and the like dispersed on low-carbon alloy martensite, and the carbon content in the matrix is controlled to be less than 0.30%.

4. The high hardness hardfacing electrode of claim 1, wherein the basic oxide and the acidic oxide in the slag form a low melting point composite compound.