Introduction
Nickel-chromium martensitic stainless steel 1Cr17Ni2 (AISI431)is a kind of stainless steel with excellent mechanical properties and corrosion resistance.In plastics industry, it has been widely used in aircraft, chemical and high-temperature components due to its satisfactory performance.In the past few decades, it has been widely studied both at home and abroad.The fracture toughness of this material is an important mechanical property.
The Fracture Toughness of 1Cr17Ni2 Steel
The fracture toughness of 1Cr17Ni2 steel is an important mechanical property affecting its performance in the use of structural components.Different methods are used to measure the fracture toughness of 1Cr17Ni2 steel, such as dynamic tension test, dynamic compression test, three-point bending test, crack closure test, plane-strain fracture toughness test, compact fracture toughness test and cylindrical compact fracture toughness test on convex corner crack specimens.
With the development of theoretical basis and experimental technology, the research on fracture toughness of 1Cr17Ni2 steel has received much attention and made great progress. Especially in recent years, studies have made use of theories and methods such as necrography, plastic deformity area, fracture mechanics, linear-elastic-plastic fracture mechanics and elastic-plastic boundary element method to apply 1Cr17Ni2 steel to engineering practice.
Dynamic tension tests and dynamic compression tests are commonly used methods to measure the fracture toughness of 1Cr17Ni2 steel. In a dynamic tension test, a specimen of 5mm in diameter and 1Cr17Ni2 steel of 12mm in length is tested under a constant rate of strain. The loading force is recorded and the fracture toughness is obtained by calculating the loading force required to fracture the specimen. In the dynamic compression test, the specimen is subjected to a ramp-shape loading under a constant rate of strain. A quasi-static force trace is acquired and the fracture toughness is determined by an energy balance analysis.
The Three-Point Bending Test of 1Cr17Ni2 Steel
The three-point bending test is a commonly used method in the study of fracture behavior of 1Cr17Ni2 steel. In this test, a specimen is placed on two support points and a load is applied in a three-point bending form to create a widened crack. The loading curve (force-deflection curve) can be measured and the fracture toughness can be obtained from the ratio of fracture force to crack opening displacement.
The Crack Closure Test of 1Cr17Ni2 Steel
The crack closure test is an established method for the analysis of fracture of 1Cr17Ni2 steel.In this test, a sharp crack is created and loaded by an increasing tensile force until the crack is completely closed.The loading curve can be recorded and the fracture toughness can be obtained from the tensile force required to close the crack.
Plane-Strain Fracture Toughness Tests and Compact Fracture Toughness Tests of 1Cr17Ni2 Steel
The plane-strain fracture toughness test is one of the most widely used methods in the study of fracture behavior of 1Cr17Ni2 steel. In this test, the specimen is loaded along its longitudinal axis to generate a widened crack, which is recorded by a displacement measuring device.The force and displacement curves can be obtained and the fracture toughness of 1Cr17Ni2 steel can be determined by analyzing the loading curves.
The cylindrical compact fracture toughness test on convex corner crack specimens is also used to measure the fracture toughness of 1Cr17Ni2 steel. In this test, a cylindrical series of curved cracks is created in a specimen and loaded to fracture.The loading characteristics of the specimen can be measured and the fracture toughness can be obtained by analyzing the force-closure displacement curve.
Conclusion
Nickel-chromium martensitic stainless steel 1Cr17Ni2 (AISI431)is extensively used in aircraft, chemical and high-temperature components due to its good performance.The fracture toughness of 1Cr17Ni2 steel is an important mechanical property. The fracture toughness of 1Cr17Ni2 steel has been studied extensively by researchers using different methods.Dynamic tension tests, dynamic compression tests, three-point bending tests, crack closure tests, plane-strain fracture toughness tests and compact fracture toughness tests have been used to measure the fracture toughness of 1Cr17Ni2 steel.The results have shown that 1Cr17Ni2 steel has a high fracture toughness and can be applied to engineering practice.
