Detection sample block

Abstract

The utility model relates to a detection sample block which is cut out in the width direction of a welding surface of a steel piston, and at least one layer is cut out; the detection sample block is of a long-strip-shaped structure and comprises stretching sections close to the upper end and the lower end and a middle section between the two stretching sections, the thickness of the stretching sections is consistent with that of the middle section, and the width of the stretching sections is larger than that of the middle section. According to the utility model, the detection sample block and the sampling method are optimized, the detection sample block can meet quantitative strength detection, and the detection condition is similar to the actual operation condition of the steel piston, so that whether the welding quality meets the design requirement or not is accurately judged, and the welding production of the steel piston can be more effectively guided.

Description

Technical Field

[0001] The utility model relates to the technical field of welding steel pistons of internal combustion engines, and more specifically to a detection sample block. Background Art

[0002] The upgrade of engine technology requires that the mechanical properties and high temperature resistance of the core engine components such as pistons, piston rings, and cylinder liners must be greatly improved to ensure the reliability of the entire engine. Among them, steel pistons have excellent mechanical properties under high temperature and high pressure operating conditions and are favored by major OEMs. In order to effectively reduce the temperature of steel pistons during actual operation and improve the fatigue strength of pistons, steel pistons currently mainly adopt a split structure design, with the head and skirt connected by welding to form a cooling oil channel, and the temperature of the entire piston is reduced by continuous circulation of cooling oil. That is, the quality of the friction welding weld of the steel piston has a great influence on the performance of the steel piston. Once there is a problem with the welding quality of the steel piston, it will cause engine failure and even cause serious consequences such as casualties.

[0003] However, for the quality evaluation of friction welding of steel pistons, the industry currently basically uses bending tests for qualitative testing, that is, the judgment result is based on the fracture position of the sample block. If the fracture position is in the non-weld area, it is judged as qualified, and if the fracture position is in the weld area, it is judged as unqualified. Due to the complex structure of the piston, the sizes and shapes of the intercepted bending specimens are different, and the bending specimens have welding flash and other factors, which will affect the bending test results. In the actual bending test of different products, fractures in the welding area often occur; such as Figure 5 As shown in the figure, the sampling position for the friction welding strength test of steel pistons is determined by the bending test adopted by the piston industry in the current market. The irregular structure of the sample block makes it difficult to perform quantitative tensile testing, and the stress conditions of the bending test are quite different from the actual operating conditions of the piston, making it impossible to truly measure whether the strength of the welding area meets the design requirements.

[0004] Therefore, it is necessary to design a test specimen for testing the strength of friction welding welds of steel pistons. Utility Model Content

[0005] The utility model mainly aims at the above-mentioned problems existing in the prior art, provides a detection sample block, optimizes the detection sample block and the sampling method, realizes the quantitative + qualitative comprehensive detection and judgment, can not only quantitatively determine the tensile strength of the weld, but also can qualitatively observe the fracture condition of the weld area, provides strong support for the quality detection technology of the steel piston weld of the internal combustion engine, and improves the accuracy and reliability of the quality detection of the friction welding weld of the steel piston.

[0006] The purpose of this utility model is mainly achieved through the following solutions:

[0007] A detection sample block, which is intercepted in the width direction of the welding surface of a steel piston and has at least one layer intercepted; the detection sample block has a strip-shaped structure, including tensile sections near the upper and lower ends and an intermediate section in the middle of the two tensile sections. The thickness of the tensile section is the same as that of the intermediate section, and the width of the tensile section is greater than the width of the intermediate section.

[0008] Preferably, the thickness range of the intermediate section is 3.5 - 5 mm.

[0009] Preferably, the width range of the intermediate section is 9.5 - 12 mm, and the width of the tensile section is 1.5 - 2 times the width of the intermediate section.

[0010] Preferably, the length of the detection sample block is not less than 40 mm.

[0011] Preferably, the transition from the intermediate section to the tensile section is smooth.

[0012] Preferably, the welding heat affected zone of the detection sample block is coated with marks.

[0013] Preferably, anti-slip lines are provided on both sides of the tensile section.

[0014] Therefore, compared with the prior art, the present utility model has the following advantages:

[0015] (1) The present utility model can meet the quantitative + qualitative detection of the strength of friction welded seams. By using precise sample block design and layered tensile tests, quantitative detection of the seam strength is achieved. At the same time, through etching treatment and color marking, it is convenient to conduct qualitative analysis on the fracture position, improving the accuracy and reliability of the detection results;

[0016] (2) The present utility model can improve the calibration efficiency. The provided detection sample block and the detection method adopted are simple, fast and efficient in operation, and can significantly reduce the detection cost and time cost;

[0017] (3) The present utility model has a wide range of applications. The provided detection sample block is not only applicable to the strength detection of friction welded piston seams, but also applicable to the strength detection of welded steel pistons such as laser welding and electron beam welding, providing strong support for the comprehensive evaluation of the quality of steel piston seams in internal combustion engines. Description of the Drawings

[0018] Figure 1 is a schematic structural diagram of the present utility model;

[0019] Figure 2 is the front view of the present utility model;

[0020] Figure 3 is the side view of the present utility model;

[0021] Figure 4 is a cross-sectional view of the present utility model;

[0022] Figure 5 is the sampling position for determining the final shape through a bending test in the current market;

[0023] Figure 6 is the sampling position of the present utility model.

[0024] Illustration: 1 - steel piston, 2 - cross-section, 3 - tensile section, 4 - middle section, 5 - heat-affected zone. Specific embodiments

[0025] The following will further specifically illustrate the technical solutions of the present utility model through specific embodiments and in combination with the accompanying drawings. It should be understood that the implementation of the present utility model is not limited to the following embodiments, and any form of modification and / or change made to the present utility model will fall within the protection scope of the present utility model.

[0026] In the present utility model, unless otherwise specified, all parts and percentages are in weight units, and the equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following embodiments are conventional methods in the art unless otherwise specified. The components or equipment in the following embodiments are general standard components or components known to those skilled in the art unless otherwise specified, and their structures and principles can be known to those skilled in the art through technical manuals or obtained through conventional experimental methods.

[0027] Embodiment 1:

[0028] As Figures 1-4 shown, the present utility model provides a technical solution, a test sample block, which is intercepted in the width direction of the welding surface of the steel piston 1 and has at least one layer intercepted; the test sample block has a long strip structure, including tensile sections 3 near the upper and lower ends and a middle section 4 between the two tensile sections 3. The thickness of the tensile section 3 is the same as that of the middle section 4, and the width of the tensile section 3 is greater than the width of the middle section 4.

[0029] When sampling, first cut along the long axis direction or short axis direction of the steel piston to be detected, and cut and obtain a test sample block containing the internal cooling oil channel weld at the cross-section 2.

[0030] Embodiment 2:

[0031] As Figures 1-4 shown, the present utility model provides another technical solution. The difference between the test sample block and that in Embodiment 1 is that the thickness range of the middle section 4 is 3.5 - 5 mm; the width range of the middle section 4 is 9.5 - 12 mm, and the width of the tensile section 3 is 1.5 - 2 times the width of the middle section 4; the length of the test sample block is not less than 40 mm.

[0032] After studying the structure of steel pistons and weld inspections, the current width of the welding surfaces of different types of steel pistons is generally between 9 - 12 mm. As Figure 6 shown, two layers are intercepted in the width direction of the piston welding surface, each layer with a thickness of 3.5 - 5 mm, a gauge width of 9.5 - 12 mm in the middle, and a length ≥ 40 mm of the test specimen block. This design ensures that the specimen block can comprehensively reflect the mechanical properties of the weld and its heat - affected zone.

[0033] Example 3:

[0034] As Figures 1-4 shown, the present utility model provides another technical solution, a test specimen block. The difference from Example 1 is that the transition from the middle section 4 to the tensile section 3 is smooth, and anti - slip lines are provided on both sides of the tensile section 3, facilitating tensile testing.

[0035] Example 4:

[0036] As Figures 1-4 shown, the present utility model provides another technical solution, a test specimen block. The difference from Example 1 is that the welding heat - affected zone 5 of the test specimen block is coated with marks.

[0037] When manufacturing the test specimen block, in the first step, the test specimen block is intercepted using the steps in Example 2; in the second step, the surface of the specimen block is ground and polished to remove processing traces and surface defects, improving the detection accuracy; in the third step, first use a 5% nitric acid alcohol solution to etch for 3 - 5 seconds to reveal the heat - affected zone 5, and use a green paint pen to paint the welding heat - affected zone 5 for subsequent observation and analysis; finally, adopt the layered tensile test detection method to detect the tensile strength of the test specimen block and check the fracture position of the specimen block. The judgment basis for the qualified detection result of the tensile specimen is as follows: there are three forms of fracture of the tensile specimen. The first is to fracture along the center of the weld, the second is to fracture along the edge of the heat - affected zone, and the third is to fracture along the base material (non - welded area); if the tensile strength before fracture in the above - mentioned forms ≥ 850 MPa, it is regarded as qualified, where 850 MPa is the piston design strength in this embodiment, and the design strength of pistons made of different materials is determined according to the actual situation.

[0038] During the above - mentioned layered tensile test, place the prepared specimen block in a tensile testing machine, perform tensile testing at a specified rate, record the tensile strength data of the specimen block, and at the same time record the maximum tensile force value before the specimen block fractures, that is, the tensile strength, observe and record the specific fracture position of the specimen block, and analyze whether the fracture occurs in the weld area or at the edge of the heat - affected zone.

[0039] The detection sample block provided by the utility model can meet the quantitative + qualitative detection of the friction welding seam strength. By adopting precise sample block design and layer-by-layer tensile test, the quantitative detection of the seam strength is realized. At the same time, through etching treatment and color marking, it is convenient to conduct qualitative analysis on the fracture position, improving the accuracy and reliability of the detection results; it can improve the calibration and detection efficiency. The provided detection sample block and the detection method adopted are simple to operate, fast and efficient, and can significantly reduce the detection cost and time cost; it has a wide range of applications. The provided detection sample block is not only applicable to the detection of the friction welding piston seam strength, but also applicable to the detection of the seam strength of steel pistons welded by laser welding, electron beam welding, etc., providing strong support for the comprehensive evaluation of the quality of the steel piston seams of internal combustion engines.

[0040] It should be understood that this embodiment is only used to illustrate the utility model and not to limit the scope of the utility model. In addition, it should be understood that after reading the content taught by the utility model, those skilled in the art can make various changes or modifications to the utility model, and these equivalent forms also fall within the scope defined by the appended claims of this application.

Claims

1. Detection sample block, characterized in that: The test specimen is intercepted in the width direction of the welding surface of the steel piston (1) and has at least one layer intercepted; the test specimen has a strip-shaped structure, including tensile sections (3) near the upper and lower ends and an intermediate section (4) between the two tensile sections (3). The thickness of the tensile section (3) is the same as that of the intermediate section (4), and the width of the tensile section (3) is greater than the width of the intermediate section (4).

2. The test block according to claim 1, wherein: The thickness range of the intermediate section (4) is 3.5 - 5 mm.

3. The inspection sample block according to claim 2, wherein: The width range of the intermediate section (4) is 9.5 - 12 mm, and the width of the tensile section (3) is 1.5 - 2 times the width of the intermediate section (4).

4. The inspection sample block according to claim 3, wherein: The length of the test specimen is not less than 40 mm.

5. The test block according to claim 1, wherein: The transition from the intermediate section (4) to the tensile section (3) is smooth.

6. The inspection sample block according to claim 1, wherein: The welding heat affected zone (5) of the test specimen is coated with a mark.

7. The inspection sample block according to claim 1, characterized in that: Anti-slip lines are provided on both sides of the tensile section (3).

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