Restoration of the cutting blade welding hard alloy
This method allows to increase the wear resistance of the blade; it becomes self-sharpening, so that the lifetime increases by 6...8 times compared to neoplasene (hardened).
Hard alloys "Sormayt-1", "Sormayt-2", В2К, GCS and other in the form of rods with a diameter of 4...7 or powder (batch: NP, NDP) stalinit, vocar, VISKHOM-9 and the other is fused to a softer bearing layer of the part.
The carrier layer picwarehouse working bodies are made of relatively soft durable steel grades 50, 65G, L-53, L-65 with tensile strength 700...800 MPa (70...80 kgf/mm2) whose hardness does not exceed 300 HB. They are relatively well amenable to hot forging and machining of carbide cutting tool.
These steels provide strength carrier layer, while the deposited solid alloy (cutting layer) has a relatively low strength, but high resistance to wear (hardness of the deposited layer of NV 750... 780). The structure of the blade with a big difference of wear resistance of bearing and cutting layers provides a self-sharpening (preserve optimum profile of the blade) picwarehouse working bodies at the expense of accelerated wear of the carrier layer and the slow wear of the cutting layer.
Self-sharpening blade is provided with a ratio of the thickness of the carrier layer to the cutting in the range of 1 : 1,2.
If this ratio is smaller, then the bearing layer will wear out quicker than cutting, and cutting a naked layer (hard alloy) will crumble. With a larger ratio of the thickness of the carrier and cutting layers will wear out faster cutting layer, previously blunt blade will appear occipital chamfer, etc.
A soil-cutting working bodies, machining of heavy soil (clay), is fused from the back side along the blade a thin layer of 1.5...2 mm width 12...25 mm, and machining light (sandy loam) soil is fused on the front side, as in the processing of loamy soil the front side of the blade wears out faster: the angle of the occipital chamfer, as a rule, does not exceed 10° at a virtually constant width.
Before welding of the blade to produce the edit items cold or the local heating it in the furnace (the fiery furnaces or electric type, STZ and STO) to a temperature of 830...850°C (light red). After editing the detail is heated to a temperature of 1000...1200°C (orange-light yellow) and retard the groove side of the blade under the hard surfacing layer. Quickdraw grooves produce special dies that create the required profile for pneumatic hammers of the type M1410 or manually on the anvil.
Forging a method of manufacturing the grooves can be replaced by milling on milling machines 6Н80Ш disc mill with plates of hard alloy T15K6 at cutting speed of 30...40 m/min and feed of 0.10...0.15 mm/tooth. The width of the grooves under the surfacing shall be equal to the difference between normal and maximum-width parts (plowshares, pen arms of the cultivator, knife plane, etc.) and a depth of 0.3...2 mm depending on the thickness of the blade, i.e. the depth of the groove should be such that the ratio of the thickness of the carrier layer of the blade towards the cutting was in the range of 1 : 1,2.
In Fig. 1 and 2 show the dimensions of the packing blade of the ploughshare and the arms of the cultivator under the surfacing. Training places under the surfacing in parts such as discs is to correct the geometric shape of the blade by way of grinding them to a thickness of 0,5 ...0,7 mm at an angle of 33° on the screw-cutting lathe (Fig. 3) or rough-grinding machines.
Fig. 1. Preparing the blade for welding: a — with straight blade; b — with a chisel blade.
Fig. 2. Preparation of chisels for surfacing.
Fig. 3. Diagram of the sharpening disk on the lathe, screw-cutting lathe: 1 — mandrel; 2 — faceplate; 3 — disk; 4 — washer; 5 — nut; 6 — cutter.
In spherical discs sharpening blades are on the convex side. Before sharpening the blade bent rims rule manually hammer plumbing on the stove: a weakened rivet is crimped with a pneumatic hammer and swages, and unfit replace with new. When you wear the square holes in the discs harrows (harrows) reduced welding arc welding electrode e-42 pads with square holes, pre-aligning the axle plates with the axis of the hole in the disk. Lining is made by forging method from the selected drives. To prevent break away of the blade with welded linings, the blade liberally cooled with a wet cloth or clay.
After Troubleshooting and training of the blade to the cladding, it is fused solid alloy with a thickness of 0,4...0,6 mm and a width of 20...25 mm. the Width of the floating layer on the blades of the disks must be equal to half the difference between normal and maximum size. Discs harrows is fused on the convex side, and drives heavy harrows — with concave, i.e. from the side opposite to the grinding chamfers. Fused (increasing) hard alloys in a variety of ways, both manually and with the help of welding-welding machines.
The essence of the gas welding of hard alloys is that the plot of blade length 80...90 mm is heated to a temperature of 850...1000 °C (orange-light red color), sprinkling it burnt brown. At the time of "fogging" of the metal make in a reducing flame (ratio of oxygen to acetylene is equal to 0,8...0,9) solid alloy in the form of a rod, moving the torch and the rod across the blade towards each other, fused wear layer on the entire width of the blade (Fig. 4).
Fig. 4. The scheme of surfacing blade blade hard alloy by means of gas burner: 1 — rod solid metal; 2 — burner; 3 — share.
The surfacing of the charge of type NP-1, NPR-1, consisting of 82...85 % powder of hard alloys and 15...18 % flux (by weight) produce lower heating blade. Freely poured a layer of the charge should be R...3.5 times thicker than the deposited layer.
The shield is fused by a burner GS-53 with tip # 4, and paws cultivators and disc harrows — burners with tips # 2 and # 3.
In manual electric arc welding freely poured a layer of mixture on the prepared blade is melted in electric arc length 4 mm 3...alternating or direct current (straight polarity) 200...250 A graphite (carbon electrode). The blade is fused with a sock: the movement of the electrode (diameter of 12...15 mm) must be zigzag (Fig. 5). After manually overlaying the deposited solid layer of compacted and leveled smithing by the way.
Fig. 5. Diagram of TIG welding blade blade powdered hard alloy: 1 — mixture; 2 — shield; 3 — graphite electrode.
The induction method of welding is more efficient than manual gas and electric welding. Heating of the mixture and the blade is high-frequency currents from 500 to 100 000 Hz. The heating rate at the specified frequency interval is equal to 1.5...6 min. Depth of the heating reaches 5 mm (Fig. 6).
Fig. 6. The scheme of induction surfacing of a powdered hard alloy: 1 — coolant 2 — filler item; 3 — charge; 4 — single-turn inductor.
Short-length sticks parts (plowshares, paws cultivators, etc.) is fused at the same time along the entire length of the blade. Picwarehouse parts such as discs fused portions with continuous rotary motion of a part in the inductor with a speed of 0,3...0,4 m/s.
MORE THAN 15,000 OF THE CONVERTED TRACTORS, COMBINES