CN113275705A

CN113275705A - Novel overlaying process for wear-resistant and impact-resistant repairing of shield machine cutter

Info

Publication number: CN113275705A
Application number: CN202110599159.XA
Authority: CN
Inventors: 徐淑波; 张世超; 张森; 任国成; 景财年
Original assignee: Shandong Jianzhu University
Current assignee: Shandong Jianzhu University
Priority date: 2021-05-31
Filing date: 2021-05-31
Publication date: 2021-08-20

Abstract

The invention relates to a novel overlaying process for repairing a shield machine cutter in a wear-resistant and impact-resistant manner. When the cutter meets the impact load of hard rock, the wear-resistant layer is broken. Aiming at the problems existing in the prior surfacing welding, the invention adopts a method of improving the content of Ni and V in the welding rod, simultaneously reducing the content of W in the welding rod, and then adding Nb element, so that the Rockwell hardness of the surfacing welding layer can reach 63-65 and the surfacing welding layer has better toughness. The cutter ring can avoid surfacing cracking, has a lower friction coefficient, enhances the binding force of the cutter ring and the cutter body, and can be widely applied to manufacturing shield machine cutters.

Description

Novel overlaying process for wear-resistant and impact-resistant repairing of shield machine cutter

Technical Field

The invention relates to a novel overlaying welding process for repairing a cutter of a shield machine in a wear-resistant and impact-resistant manner, which makes progress in the field of mechanical properties of materials, and particularly relates to a method for repairing the cutter.

Background

The method for tunneling the tunnel by the shield expands the breadth of the construction method of the tunnel engineering and enables the tunnel construction to enter an automatic construction stage. When the shield machine is used for tunneling, the rock or soil is cut mainly by means of the extrusion and shearing actions of the cutter, so that the performance of the cutter becomes a decisive factor influencing the shield construction progress. The shield machine inevitably causes cutter wearing and tearing inefficacy in the construction. After the cutter is worn and failed, the shield machine must stop working. The method analyzes the reason of the abrasion of the cutter, improves the structure, the material and the manufacturing process of the cutter and is beneficial to prolonging the service life of the shield machine cutter. On the basis of analyzing the wear reasons of the shield machine cutter, the invention provides some measures for repairing the cutter in a targeted manner, thereby providing a new scheme for developing a more wear-resistant and more practical cutter.

When the shield machine cutter works in a tunnel, the stratum penetrated by the tunnel is mainly clay sand mixed with coarse sand, gravel sand and pebbles, the sandy soil has large friction resistance and strong permeability, water is quickly discharged under the pushing and extruding of the shield machine, the soil body strength is improved, so that the shield machine has large pushing friction resistance, the pressure of excavation face soil is also large, and the abrasion to the cutter head is serious. And moreover, the abrasion resistance of the base body of the outer edge scraper is not enough, and hard alloy falls off after abrasion, so that the cutter head bears direct abrasion.

Welding technology, also known as joining engineering, is an important material processing technology. Welding is defined as a process in which the material of the workpieces to be welded (homogeneous or heterogeneous) is bonded atomically by applying heat or pressure or a combination of both, with or without a filler material, to form a permanent bond. Surfacing is a welding process, is an economical and rapid process method for modifying the surface of a material, and is increasingly widely applied to manufacturing and repairing parts in various industrial departments. In order to most effectively exert the function of the overlay layer, it is desired to adopt an overlay welding method having less dilution of the base material, a higher deposition rate, and excellent overlay performance, that is, a high-quality and high-efficiency overlay welding technique.

Disclosure of Invention

The novel surfacing process for the wear-resistant impact-resistant repair shield machine cutter is characterized in that the Ni content and the V content in a welding rod are improved, the W content in the welding rod is reduced, then Nb element is added, the Rockwell hardness of a surfacing layer can reach 63-65, the surfacing layer has better toughness, surfacing cracking can be avoided, a lower friction coefficient can be achieved, and meanwhile the binding force between a cutter ring and a cutter body is enhanced.

A novel overlaying process for a wear-resistant impact-resistant repairing shield machine cutter is characterized in that chemical components of deposited metals of welding rods in overlaying are (%) C: 0.5, Si: 0.3, Mn: 0.5, Cr: 4, W: 6, Mo: 2.5, V: 2, Nb: 7, Ni: 4, the balance of mineral mixture such as marble, fluorite quartz, rutile and the like, and the strength and the toughness of the welding seam are obviously improved by V, Ni and Nb in the welding rod.

The bead welding process for repairing the cutter of the shield machine adopts a submerged arc bead welding mode to the ring surface of the side plate on the outer edge of the shield machine cutter body, firstly fills a circle of groove, then bead welds the whole ring surface of the side plate, and forms a circle of wear-resistant layer on the ring surface.

The chamfer wearing and tearing of cutter neighboring adopt the mode of adding the wear-resisting steel sheet of welding round to resume the reinforcement to it, and steel ring face and cutter head body face parallel and level, steel ring and cutter body welding adopt carbon dioxide protection to weld, fill and level up the recess between the gap between steel ring and the cutter panel and steel ring and the cutter outer fringe curb plate anchor ring with submerged arc surfacing.

The invention is characterized in that the addition of V, Ni and Nb elements ensures that the deposited metal of the welding rod has good mechanical property, V ensures that a welding seam obtains a large amount of fine and uniform ferrite tissues, Nb can refine crystal grains and reduce the overheating sensitivity and the tempering brittleness of steel, and can improve the welding property, but the plasticity and the toughness are reduced, Ni improves the oxidation resistance and the toughness, and simultaneously makes up the defects brought by the Nb element.

The invention is characterized in that a submerged arc surfacing mode is adopted, the invention has the advantages of perfect protection, small energy loss, high productivity and good weld seam formation, a circle of groove is filled first, then the whole ring surface of the side plate is surfaced, and finally a circle of wear-resistant layer is formed on the ring surface, so that the diameter of the body can be recovered to the factory.

The invention is characterized in that the welding of the steel ring and the cutter body adopts carbon dioxide arc welding, the surface of the steel ring adopts carbon dioxide arc welding to bead weld a grid-shaped wear-resistant bead weld layer, and simultaneously, the elements of V, Ni and Nb can effectively reduce the friction coefficient and enhance the binding force of the cutter ring and the cutter body.

Detailed Description

A novel overlaying process for a wear-resistant impact-resistant repairing shield machine cutter is characterized in that chemical components of deposited metals of welding rods in overlaying are (%) C: 0.5, Si: 0.3, Mn: 0.5, Cr: 4, W: 6, Mo: 2.5, V: 2, Nb: 7, Ni: 4, the balance of mineral mixture such as marble, fluorite, quartz, rutile and the like, and the strength and the toughness of the welding seam are obviously improved by V, Ni and Nb in the welding rod.

Claims

1. A new type of surfacing process for repairing shield machine tools with wear resistance and impact resistance, which is characterized in that the content of Ni and V in the electrode can be increased, the content of W in the electrode can be reduced simultaneously, and then Nb element is added to make the surfacing layer. Rockwell hardness reaches 63-65, and has good toughness, which can not only avoid surfacing cracking, but also have a lower friction coefficient, and at the same time enhance the bonding force between the cutter ring and the cutter body;

(a) The surfacing process of a new type of wear-resistant and impact-resistant repairing shield machine tool. The chemical composition of each deposited metal of the electrode in surfacing welding is (%) C: 0.5, Si: 0.3, Mn: 0.5, Cr: 4, W: 6, Mo: 2.5, V: 2, Nb: 7, Ni: 4, the rest are mineral mixtures such as marble, fluorite, quartz, rutile, etc. V, Ni, and Nb in the electrode make the strength and toughness of the weld remarkable improve;

(b) To repair the surfacing welding process of the shield machine tool, use the submerged arc surfacing method for the outer edge side plate annulus of the shield tool body. First fill a circle of grooves, and then surfacing the entire side plate annulus. A ring of wear-resistant layer is formed on the ring surface;

(c) The chamfering wear of the outer peripheral edge of the tool is restored and reinforced by welding a ring of wear-resistant steel plate. The surface of the steel ring is flush with the surface of the cutter body. Submerged arc surfacing fills the gap between the steel ring and the tool panel and the groove between the steel ring and the outer edge side plate of the tool.

2. The surfacing process of a new type of wear-resistant and impact-resistant repairing shield machine tool according to claim 1 is characterized in that the addition of V, Ni, and Nb elements makes the electrode deposited metal have good mechanical properties, and V makes A large number of small and uniform ferrite structures are obtained in the weld. Nb can refine the grains and reduce the overheating sensitivity and temper brittleness of the steel, which can improve the welding performance, but the plasticity and toughness are reduced. Ni improves the oxidation resistance and Toughness, while making up for the deficiencies brought by the Nb element.

3. The surfacing process of a new type of wear-resistant and impact-resistant repairing shield machine tool according to claim 1, characterized in that the method of submerged arc surfacing is adopted, which has the advantages of perfect protection, small energy loss, high productivity, and welding seam forming. Good advantage, first fill a circle of grooves, then surfacing the entire side plate annulus, and finally form a circle of wear-resistant layers on the annulus, which can restore the body diameter to the factory.

4. The surfacing welding process of a novel wear-resistant and impact-resistant repairing shield machine tool according to claim 1 is characterized in that carbon dioxide shielded welding is adopted for welding the steel ring and the tool body, and carbon dioxide shielded welding surfacing grid is adopted on the surface of the steel ring. At the same time, the V, Ni, Nb elements can effectively reduce the friction coefficient, and at the same time enhance the bonding force between the cutter ring and the cutter body.