Production Process Specification Of Titanium And Titanium Alloy Forging
1、 Preparation of ingot
1. After receiving the production operation plan, the production technologist should carefully review part of the plan. If there is any problem, communicate with the planner in time. After confirming that there is no error, the production process can be prepared. And inform relevant personnel to the warehouse to pick up materials.
2. According to GB / 3620.1 titanium and titanium alloy grades, chemical composition and allowable deviation of chemical composition (GB / 3620.2) and relevant provisions of enterprise standard, the material receiving personnel shall check the ingot certificate, and check whether the alloy brand, ingot number, specification and weight are consistent with the real object, and then transfer the material after confirmation.
3. The ingots should be placed in order when they are transferred into the forging workshop. The marks should be placed in the visible position or the ingot number should be marked clearly on both ends or surface of the ingot with metal (marking pen)
Before feeding, the production technologist should carefully study the technical standard of the product to ensure that its chemical composition can meet the technical requirements of the product. Otherwise, it cannot be fed.
5 after the ingot is transferred to the forging workshop, the furnace workers must coat the ingot before charging. When coating, the ingot shall be padded up with pad wood or guide roller, and the impurities and oil stains on the ingot surface shall be cleaned with cleaning agent, and then the anti-oxidation coating shall be applied.
6. When coating, do not apply the place where the ingot number is written, so as to confirm whether the ingot number is correct before charging.
The thickness of the coating should be controlled within 0.2-0.4 mm. The coating must be completely dry, that is, 24 hours before loading.
2、 Heating
Heating equipment: natural gas furnace, resistance furnace.
2 preparation before heating.
2.1 before charging the furnace, carefully check whether the brand, ingot number, specification and number of pieces of incoming materials are consistent with the process card, and the furnace can be loaded after confirmation.
2.2 the heating equipment and temperature measuring instrument shall operate normally, otherwise they shall not be used. The temperature measuring instrument shall be calibrated once every half a year and checked frequently. For scientific research materials or important products, the furnace temperature should be checked before production. When the furnace starts to use after overhaul or long-term shutdown, the furnace temperature shall be checked. The average temperature zone of the furnace shall be checked once a quarter under normal conditions, and records shall be made.
2.3 the furnace shall be clean before charging, and there shall be no steel and other non-metallic materials, oxide scales of these metals and other substances that affect the heating quality. The surface of ingot should be clean and free of oil and other dirt.
3、 Forging
1 forging equipment: 2000t hydraulic press 750 kg air hammer
2 preparation before forging
2.1 before production, the operator should first check the equipment operation record, and test run to check whether the equipment operates normally. If there is any problem, the maintenance worker should be informed to deal with it.
2.2 each member of the team shall make clear the production task of the shift, understand the process requirements on the process card, and formulate the forging sequence of the shift.
2.3 each member shall prepare the necessary tools for production according to their own responsibilities. Such as tongs, molds, throw, punch, chopper, caliper, ruler, etc.
2.4 for some alloy materials or small size materials (small material temperature drop quickly), before forging, hammers, tumblers, punches, choppers and other tools should be fully preheated in the temperature range of 150 ~ 300 ℃ to ensure the forging quality and prevent cracks.
3. Titanium rod forging
3.1 the main forging process of bar is stretching, and the whole forging process can be divided into open blank forging, intermediate (semi-finished) forging and finished forging. The first heat forging of ingot is called open forging, and the rest is intermediate forging and finished forging.
3.2 when the ingot is opened, the first step is light forging and fast forging. The reduction per stroke should be small. The pure titanium should not exceed 80 mm and the alloy should not exceed 60 mm each time. When the total deformation reaches 20-30% (forging ratio 1.25-1.43), the reduction per stroke can be increased, 80-100 mm for pure titanium and 60-80 mm for alloy. When the deformation is basically completed or the temperature is quite low, the deformation amount should be gradually reduced to avoid Cracks are produced.
3.3 during normal forging and drawing, the feeding amount (LO) is generally 0.75 of the hammer head width (b), that is, Lo = 0.75b. For example, for a 2000t hydraulic press, if B = 400mm, then Lo = 0.75b = 338MM, and the reduction should not be greater than 2 / 3 of the feed, that is, ho-h = 2 / 3 lo. In order to avoid folding, it is necessary to polish, waste manpower and affect the yield. If the process card does not require full hammer head forging, it is generally treated as normal forging.
3.4 the blank should be chamfered in the first fire of finished products (products that can be delivered after smashing round), i.e. octagonal or twelve square billets. The size should be appropriate, not too large or too small. If the size is too large, it is easy to fold and can not complete the process of smashing the circle. If it is too small, it can not meet the size of the finished product.
3.5 the forging of finished bar is mainly round breaking. During the first round breaking, it should be pressed gently to avoid bending. For the second time, the reduction should be increased. Each bar should be pressed at least three times to ensure the tolerance of outer diameter required by the process card, and the residual heat of blank should be used for straightening. If the material temperature is too low, but the bending degree does not meet the requirements, it can be reheated for straightening. The heating temperature of straightening is generally 150-200 ℃ below the phase transformation temperature. The holding time depends on the size of the material. The bar that needs annealing can be straightened at the temperature when it is discharged from the furnace after annealing.
3.6 bending requirements: there are no special requirements for the bending degree of blank after billet opening and intermediate forging. When forging finished products, the bending degree of bars delivered in black skin shall be no more than 6 mm / m. For bars delivered with bare bars, the bending shall not be greater than 3 mm / m.
3.7 after forging, heat cutting shall be carried out according to the required length of process card. Because, if the temperature is too high, it is not easy to cut off and easy to deform, which will affect the size of the blank. If the temperature is too low, the pressure required is large and it is not safe. The cutting angle of both ends shall not be greater than 10% of the straight diameter, and there shall be no obvious horseshoe shape. Hot cutting is not used for finished bar.
3.8 the cut material head must be weighed, and the weight should be filled in the process card.
