Low-temperature box for middle-size and large-size test pieces

Abstract

The invention discloses a low-temperature box for middle-size and large-size test pieces. The low-temperature box comprises a cold insulation barrel body, a cold insulation layer, a heat insulation box, a cold insulation barrel cover assembly, a test piece hanging bracket assembly, an outer frame, a liquid discharging pipe valve assembly and a barrel body connecting block, wherein the cold insulation barrel cover assembly covers the top of the cold insulation barrel body and can rotate around the cold insulation barrel body; the cold insulation barrel cover assembly is provided with a temperature sensor, a stirring rod, a cooling medium pipe assembly and a top cover handle; temperature and liquid level measurement and control, and stirring of cooling liquid can be realized; the test pieceis hung and fixed at the lower part of the test piece hanging bracket assembly located at the center of the cold insulation barrel cover assembly and is inserted into a cooling medium of the cold insulation barrel body to be cooled; the cold insulation layer covers the cold insulation barrel body, and the cold insulation layer and the cold insulation barrel body are embedded into the heat insulation box; the heat insulation box is embedded into the outer frame.

Description

technical field [0001] The application relates to a device for testing the mechanical properties of steel and welded joints, in particular to a low-temperature box for medium and large-sized test pieces, which is used for testing and testing the low-temperature mechanical properties of steel and welded joints. Background technique [0002] Tests such as drop weight and CTOD are used to more accurately evaluate the resistance of steel structures by measuring the non-plastic transition temperature of full-scale or near-full-scale specimens of steel structure base metals, welding consumables, and welded joints and the opening displacement of crack tips at specified low temperatures. A common method for low temperature brittle fracture properties. Lowering the test piece to the specified low temperature is an important step in these tests, due to the large size of the full-size or near-full-size test piece. [0003] The cooling of the test piece mainly adopts the method of imme...

AI Technical Summary

Problems solved by technology

[0004] There are two main types of existing low-temperature boxes (tanks), one is a simple rectangular low-temperature tank, which basically has a top-open structure, and generally uses low-thermal-conductivity organic sheet bonding or hot-melt welding at low temperatures (greater than -60°C). Production, at cryogenic temperature (-60~-196°C), use internal and external low-temperature steel plates to sandwich insulation materials (the processing and production procedures are cumbersome and demanding, otherwise the cold insulation effect will not be good). When using, remove the top cover and put the test Put the parts into the tank, add cooling medium, and adjust the temperature of the cooling liquid. Then, buckle the top cover to keep warm and cool. After the specified time, lift the top cover, and the tester will go deep into the cooling medium with hands or tools to take out the test piece. The corresponding test has the advantage of low cost, but the insulation (cold) design of the box (trough) is not perfect. During the test, the operator must operate above or in the large open coolant level. Large volume loss, large cooling medium usage and high loss, poor operation standardization, and high risk of frostbite

The other type is professional low-temperature tank equipment, which is produced by professional manufacturers. According to the minimum operating temperature, it is divided into two types: compressor refrigeration (>-100°C) and liquid nitrogen refrigeration (≤-100°C). It has automatic temperature control , accurate temperature control, etc., but most of the equipment is suitable for precision device testing such as low-temperature sensors or small specimens (10*10*55mm) for Charpy impact tests. Equipment suitable for medium and large-sized specimens needs to be customized, and the cost is high. The test temperature range of 0~-196°C generally needs to be equipped with two types of equipment, which is suitable for laboratories that carry out a large number of low-temperature tests continuously for a long time, otherwise the cost of equipment maintenance is high and the economy is poor

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