JB/T 2980.1-1999 This standard is a revision of JB 2980-81 "Test Method for High Temperature Thermal Deformation of Investment Casting Shell". During the revision, only editorial changes were made according to relevant regulations, and the main technical content remained unchanged. This standard specifies the method for measuring the thermal deformation value of the shell under a certain load, from room temperature to 1300℃, at various temperatures. JB/T 2980.1-1999 Test Method for High Temperature Thermal Deformation of Investment Casting Shell JB/T2980.1-1999 Standard download decompression password: www.bzxz.net

JB/T2980.1-1999
This standard is a revision of JB2980--81 "Test method for hot deformation of investment casting shell". During the revision, editorial changes were made to the original standard, and the main technical content remained unchanged. This standard replaces JB2980--81 from the date of implementation. This standard is proposed and managed by the National Technical Committee for Casting Standardization. The drafting units of this standard are: Shenyang Foundry Research Institute and Tsinghua University. 461
1 Scope
Machinery Industry Standard of the People's Republic of China
Test method for hot deformation ofinvestment casting shell
JB/T2980.1---1999
Replaces JB2980-81
This standard is applicable to the determination of the thermal deformation value of the shell under a certain load, from room temperature to 1300℃, at different temperatures. 2 Instruments and Equipment
The test instrument is RKB-shell high temperature deformation instrument. 2.1 The instrument should work in a clean environment without strong magnetic and electric fields, strong vibration and high temperature. 2.2 The heating element of the high temperature furnace of the instrument is a silicon carbon rod, and its maximum operating temperature is 1350C. 2.3 The load error of the sample is 1% to 3%. 3 Preparation of the sample
3.1 The shape and size of the sample are shown in Figure 1.
3.2 After the sample is assembled with the two wax molds shown in Figure 2, about six layers of shell material are applied on the inner wall of the wax mold to make the shell thickness slightly more than 6mm, and then the sample is scraped flat along the inner mouth of the wax mold to ensure that the sample thickness is 6mm. 3.3 After the sample is dewaxed, it is dried at 110C and kept warm for 2h. 4 Test Steps
4.1 Adjust the measuring rod to the plumb position, adjust the leveling screw mechanism, and make the bubble of the level in the "center" position (or within the dividing line of the bubble). bzxz.net
4.2 When conducting the test, place the standard block with a hole in the center on the specimen seat, then move the loading component so that the loading rod can fall into the hole of the standard block when it descends. Fix the loading component, then loosen the screw fine-tuning mechanism in a counterclockwise direction, lift the loading rod, remove the standard block, and place the specimen horizontally on the specimen seat so that the load applied to the specimen by the loading rod is located at the center of the specimen surface. 4.3 After checking the performance of each instrument, turn the heating speed switch on the temperature control instrument to the required position and start heating the sample. As the temperature rises, the deformation of the sample will be displayed and recorded on the inductance displacement meter and the double pen recorder. Calculation of results Since the entire instrument system and the loading rod will also have a certain amount of deformation after heating, the displacement of the loading rod is not equal to the deformation of the sample, and the "blank test" data under the same conditions needs to be subtracted. 6
Test record
The test record should include: sample name, sample number, test temperature and its corresponding sample thermal deformation value, inspection date, and inspection personnel. 163
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