CN205103105U - Xenogenesis pipe welding connects high temperature strength and notch sensitivity test sample - Google Patents

Abstract

The utility model relates to a xenogenesis pipe welding connects high temperature strength and notch sensitivity test sample, test sample include the clamping part at both ends and are located the test portion between the clamping part, having a welding seam in the test portion, being located welding seam one side and having low alloy steel side melt run, the welding seam opposite side has high alloy steel side melt run, low alloy steel side melt run is equipped with the breach with the juncture at test portion edge. The utility model discloses a test sample with the breach setting in first melt run, also be low alloy steel with the boundary line of welding seam metal on, can guarantee that test sample ftractures along first melt run, the fracture condition during with the in -service use is consistent to record xenogenesis pipe welding strength of joint and to the sensitiveness of breach.

Description

Test specimens for high temperature strength and notch sensitivity of welded joints of dissimilar steel pipes

technical field

The utility model relates to the field of testing the welding performance of materials, in particular to a sample for testing the high-temperature strength and notch sensitivity of welded joints of small-diameter and thin-walled dissimilar steel pipes.

Background technique

With the development of my country's electric power industry, many high-parameter and large-capacity thermal power units have been put into operation one after another. The internal working environment of power plant boilers is even harsher, and higher requirements are placed on materials. The superheater and reheater tubes of power plant boilers often use high-alloy steel pipes in locations with harsh environments, while low-alloy steel pipes are often used in other locations. This is bound to exist dissimilar steel welded joints. The strength, safety, reliability and service life of these dissimilar steel welded joints have always been a matter of great concern to domestic and foreign design, manufacture, operation, maintenance, supervision and inspection personnel. With the long-term operation of high temperature and high pressure, the safety problem of dissimilar steel welded joints has become increasingly prominent. It is mainly manifested in the decline of its high-temperature strength and the sensitivity to notches with the long-term operation at high temperature and high pressure. Studying and mastering the performance change law of dissimilar steel welded joints under high temperature and high pressure for a long time has important theoretical value and practical significance for ensuring the safe operation of high temperature metal parts.

Conventional test specimens for dissimilar steel welded joints include weld seam, heat-affected zone and base metal. The performance of dissimilar steel welded joints affects its safe operation. In order to study the properties of the weld metal, it is usually necessary to perform performance testing on the weld metal. The conventional tensile testing includes test methods such as normal temperature tensile, high temperature tensile and enduring strength. Due to the difference in metal materials on both sides of the weld and the strength of the weld metal is much higher than that of the base metal and the heat-affected zone, conventional tensile samples are generally broken in the heat-affected zone of the weld on the side of the low-alloy steel, which is lower than the actual operation. Alloy side fusion line cracking does not match. Moreover, the cross-sectional area of the test section is generally constant, and the sensitivity of the metal to the notch near the fusion line of the dissimilar steel welded joint cannot be obtained.

Therefore, relying on years of experience and practice in related industries, the inventor proposes a test sample for the high-temperature strength and notch sensitivity of welded joints of dissimilar steel pipes to overcome the defects of the prior art.

Utility model content

The purpose of this utility model is to provide a test sample for high-temperature strength and notch sensitivity of welded joints of dissimilar steel pipes, which ensures that the fracture of the sample occurs on the fusion line on the low alloy side, thereby accurately measuring the strength and notch of the welded joints of dissimilar steels sensitivity.

The purpose of this utility model is achieved in this way, a test sample for high temperature strength and notch sensitivity of welded joints of dissimilar steel pipes, the test sample includes clamping parts at both ends and a testing part between the clamping parts; There is a weld on the test part, the test part on the first side of the weld has a first fusion line, and the test part on the second side of the weld has a second fusion line; A gap is provided at the junction of the first fusion line and the edge of the testing part.

In a preferred embodiment of the present utility model, the notch is located in the middle of the length direction of the testing part.

In a preferred embodiment of the present invention, the notch is located on one side of the testing portion in the width direction.

In a preferred embodiment of the present utility model, the clamping part is flat, and the cross section of the clamping part perpendicular to the length direction is rectangular; the testing part is arc-shaped, and the testing The cross-section perpendicular to the length direction is arc-shaped.

In a preferred embodiment of the present utility model, the structure of the clamping part at both ends is the same, the width of the clamping part is 25 mm, and the length is 30 mm; the width of the test part is 10 mm; The thickness is the same as the thickness of the clamping part; the length of the test part is 15mm-30mm; a smooth transition section concave in the width direction is provided between the clamping part and the test part; the clamp The holding part is provided with pin holes; the total length of the test sample is 110mm-130mm.

In a preferred embodiment of the present utility model, the notch is a V-shaped notch, the depth of the notch is 2mm-3mm, the angle between the two sides of the notch is 60°, and the tip radius of the notch is 0.01mm-1mm.

In a preferred embodiment of the present invention, the material at the weld is weld metal, the material on the first side of the weld is low-alloy steel; the material on the second side of the weld is high-alloy steel steel; the first fusion line is the boundary line between the low alloy steel and the weld metal; the second fusion line is the boundary line between the high alloy steel and the weld metal.

From the above, the test sample of the utility model sets the notch on the first fusion line, that is, the boundary line between the low alloy steel and the weld metal, and more preferably sets the first fusion line in the middle of the test part , which can ensure that the test sample cracks along the first fusion line, which is consistent with the cracking situation in actual use, so as to measure the strength of the welded joint of dissimilar steel pipes and its sensitivity to notch. It can provide a basis for evaluating the safety of dissimilar steel pipe welded joints in long-term operation under high temperature and high pressure. It solves the problem that the traditional sample cannot measure the sensitivity to the notch at the fusion line of the dissimilar steel welded joint. At the same time, the sample processing is simple, and the test process is basically the same as the conventional tensile test method.

Description of drawings

The following drawings are only intended to illustrate and explain the utility model schematically, and do not limit the scope of the utility model. in:

Fig. 1: is the structural representation of the test sample of the utility model.

Figure 2: is a partially enlarged schematic diagram of the gap at I in Figure 1, showing an orthographic view of the gap.

detailed description

In order to have a clearer understanding of the technical features, purposes and effects of the utility model, the specific implementation of the utility model is now described with reference to the accompanying drawings.

Oxidation cracks often exist at the fusion line of low-alloy steel in welded joints of dissimilar steel pipes, and gradually expand under the action of stress until failure occurs. Therefore, there is a need for a test sample that can accurately measure the strength of welded joints of dissimilar steel pipes and its sensitivity to notches. As shown in Figure 1, the utility model provides a test sample 10 for the high-temperature strength and notch sensitivity of welded joints of dissimilar steel pipes. Part 1; there is a weld 3 on the test part 1; the left and right direction in the figure is the longitudinal direction of the test sample 10, and the weld 3 has a certain length in the longitudinal direction. The test part 1 on the first side of the weld 3 has a first fusion line 4, and the test part 1 on the second side of the weld 3 has a second fusion line 5; the junction of the first fusion line 4 and the edge of the test part 1 A notch 6 is provided at the test part 1, and the first fusion line 4 extends in the test part 1 and intersects with the outer wall of the test part 1 to form a borderline on the outer wall of the test part 1, and the notch 6 is set at the border line. Because the notch 6 is set on the first fusion line 4, it can ensure that the test sample 10 is cracked along the first fusion line 4, which is consistent with the cracking situation in actual use, so as to measure the strength of the welded joint of dissimilar steel pipes and its relative strength. Notch Sensitivity.

More preferably, the notch 6 is located in the middle of the test part 1 in the length direction. Such setting is more beneficial to ensure that the test sample 10 cracks along the first fusion line 4 .

As one of the specific embodiments, the clamping portion 2 at both ends of the test sample 10 has the same structure, the clamping portion 2 is flat, and the cross section of the clamping portion 2 perpendicular to the length direction is rectangular; the testing portion 1 has a certain The arc shape of the arc, the cross-section c of the test part 1 perpendicular to the length direction is a circular arc, and the thickness is the original wall thickness of the pipe (the welded dissimilar metal pipes that make the test sample). The clamping part 2 has a width of 25 mm and a length of 30 mm; the test part 1 has a width of 10 mm; the thickness of the test part 1 is the same as that of the clamping part 2, and the thickness of the pipe wall can be used. The length of the test part 1 is 15 mm-30 mm; a smooth transition section 7 recessed inward in the width direction is provided between the clamping part 2 and the test part 1 . That is, the overall shape of the test sample 10 is a strip shape with thick ends and a thin middle. The clamping part 2 is provided with a pin hole 21, which is convenient for connecting with a test instrument. The total length of the test specimen 10 is 110mm-130mm. As shown in Figure 2, the notch 6 is a V-shaped notch, located on one side of the width direction of the test section 1 (the up and down direction in Figure 1 is the width direction), the depth D of the notch 6 is 2mm-3mm, the two sides of the notch 6 The included angle α is 60°, and the tip radius r of the notch 6 is 0.01mm-1mm.

This embodiment relates to a test sample 10 of a welded joint of dissimilar steel pipes, and the dissimilar steel pipes are composed of low-alloy steel pipes and high-alloy steel pipes welded together. Low alloy steel is relative to carbon steel. On the basis of carbon steel, in order to improve one or several properties of steel, one or several alloying elements are intentionally added to steel. When the amount of alloy added exceeds the usual content of carbon steel normal production methods, the steel is called alloy steel. When the total amount of alloy is less than 5%, it is called low alloy steel. Alloy content between 5-10% is called medium alloy steel; more than 10% is called high alloy steel. The fusion line is the outline of the weld seam shown by the macroscopic corrosion of the cross-section of the welded joint. It is the dividing line between the weld metal and the base metal. The actual weld boundary should be the boundary between the semi-melted zone and the fully molten weld zone. In this embodiment, the material at the weld 3 is weld metal, the material on the first side of the weld 3 is low-alloy steel; the material on the second side of the weld 3 is high-alloy steel; the first fusion line 4 is low-alloy steel. The boundary line between the alloy steel and the weld metal, that is, the fusion line on the low alloy steel side; the second fusion line 5 is the boundary line between the high alloy steel and the weld metal, that is, the fusion line on the high alloy steel side. In addition, the test sample 10 can also be used to measure the strength of the welded joint between other dissimilar materials and its sensitivity to the notch. Correspondingly, the notch 6 can be set at the fusion line that is prone to fracture.

The test operation procedure of the test sample in this embodiment is the same as the conventional high temperature long-term tensile test method, the difference lies in the preparation of the test sample. The processing of this test sample can be roughly divided into three steps: the first step is to process the conventional sheet-shaped durable sample with an arc-shaped test part and a rectangular clamping part according to the size, so that the low-alloy side fusion line (that is, the first Fusion line) is located in the middle of the test part, pay attention to keep a certain margin; the second step is to use an appropriate etchant to corrode the low-alloy side weld and base metal to determine the exact position of the low-alloy side fusion line; In three steps, a notch is processed at the junction of the fusion line on the low alloy side and the edge of the test part.

From the above, the test sample of the utility model sets the notch on the first fusion line, that is, the boundary line between the low alloy steel and the weld metal, and more preferably sets the first fusion line in the middle of the test part , which can ensure that the test sample cracks along the first fusion line, which is consistent with the cracking situation in actual use, so as to measure the strength of the welded joint of dissimilar steel pipes and its sensitivity to notch. It can provide a basis for evaluating the safety of dissimilar steel pipe welded joints in long-term operation under high temperature and high pressure. It solves the problem that the traditional sample cannot measure the sensitivity to the notch at the fusion line of the dissimilar steel welded joint. At the same time, the sample processing is simple, and the test process is basically the same as the conventional tensile test method.

The above descriptions are only illustrative specific implementations of the present utility model, and are not intended to limit the scope of the present utility model. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention shall fall within the protection scope of the present invention.

Claims (7)

1. heterogenous steel pipe welding joint elevated temperature strength and a notch sensitivity test sample, described test sample comprises the clamping part at two ends and the test department between described clamping part; Described test department has a weld seam, it is characterized in that, the described test department being positioned at described weld seam first side has the first melt run, the described test department being positioned at described weld seam second side has the second melt run; The intersection at described first melt run and described test department edge is provided with breach.

2. heterogenous steel pipe welding joint elevated temperature strength as claimed in claim 1 and notch sensitivity test sample, it is characterized in that, described breach is positioned at the centre position of the length direction of described test department.

3. heterogenous steel pipe welding joint elevated temperature strength as claimed in claim 2 and notch sensitivity test sample, it is characterized in that, described breach is positioned at the side of the Width of described test department.

4. heterogenous steel pipe welding joint elevated temperature strength as claimed in claim 3 and notch sensitivity test sample, it is characterized in that, described clamping part is tabular, and described clamping part is rectangle perpendicular to the xsect of length direction; Described test department is the arc with radian, and described test department is circular arc perpendicular to the xsect of length direction.

5. heterogenous steel pipe welding joint elevated temperature strength as claimed in claim 4 and notch sensitivity test sample, it is characterized in that, the described clamping part structure at two ends is identical, and the width of described clamping part is 25mm, length is 30mm; The width of described test department is 10mm; The thickness of described test department is identical with the thickness of described clamping part; The length of described test department is 15mm-30mm; The rounding off section of indent is in the direction of the width provided with between described clamping part and described test department; Described clamping part is provided with pin hole; The total length of described test sample is 110mm-130mm.

6. the heterogenous steel pipe welding joint elevated temperature strength according to any one of claim 1 to 5 and notch sensitivity test sample, it is characterized in that, described breach is V-notch, the degree of depth of described breach is 2mm-3mm, the angle of two sides of described breach is 60 °, and the tip radius of described breach is 0.01mm-1mm.

7. the heterogenous steel pipe welding joint elevated temperature strength according to any one of claim 1 to 5 and notch sensitivity test sample, is characterized in that, the material of described commissure is weld metal, and the material of described weld seam first side is low alloy steel; The material of described weld seam second side is high-alloy steel; Described first melt run is the boundary line of low alloy steel and weld metal; Described second melt run is the boundary line of high-alloy steel and weld metal.