Method for detecting surface defect depth of cast iron part

Abstract

The invention relates to a method for detecting the depth of a surface defect of a cast iron part, which comprises the following steps of: measuring the volume of a colored penetrant by using the colored penetrant, a colored developer and a black marking pen in combination with a volume burette, and finally calculating the depth of the defect. The method is easy and convenient to operate, accurate in result and suitable for cast iron parts of various shapes and sizes.

Description

Technical Field

[0001] The present application belongs to the technical field of surface defects of parts, and specifically relates to a method for detecting the depth of surface defects of cast iron parts. Background Art

[0002] In industrial production, the quality control of cast iron parts is very important. There may be defects such as cracks and pores on the surface of cast iron parts, which will affect the mechanical properties and service life of the parts.

[0003] For example, a cast iron crankshaft for a marine engine with announcement number CN221221112U, authorized on June 25, 2024, includes a main journal, a stud is installed on one side of the main journal, a crank is installed on the other side of the main journal, a connecting rod journal is installed on one side of the crank, a reinforcement sleeve is provided on the outside of the connecting rod journal, a reserved hole is provided on the inner side of the reinforcement sleeve, a positioning bolt is installed inside the reserved hole, a mounting hole is provided on the inner side of the connecting rod journal, and a shaft ring is installed on the outer side of the mounting plate.

[0004] The crankshaft in the above patent, after processing, the traditional surface defect detection method mostly relies on naked eye observation or simple tool measurement, which cannot accurately quantify the depth of the defect. Therefore, it is particularly important to develop a simple, efficient and accurate surface defect depth detection method. Summary of the invention

[0005] The technical problem to be solved by the present application is: to overcome the deficiencies of the prior art and to provide a method for detecting the depth of surface defects of cast iron parts. The detection method is simple, efficient and accurate, and improves the detection efficiency and the utilization rate of parts.

[0006] The technical solution adopted by this application to solve the problems existing in the prior art is:

[0007] A method for detecting the depth of surface defects of a cast iron part comprises the following steps:

[0008] 1) Spray the colored penetrant onto the surface defective position of the cast iron parts;

[0009] 2) After the predetermined time, use a clean paper towel to remove the colored penetrant on the surface defects;

[0010] 3) Spray the colored developer evenly on the surface defect location;

[0011] 4) After a predetermined time, the surface defect position displays the defect shape;

[0012] 5) Use a black marker to mark the contour shape of the surface defect;

[0013] 6) Use a clean paper towel to remove the colored developer, leaving the outline of the surface defect marked with a black marker pen;

[0014] 7) Use a volumetric burette filled with colored penetrant to gradually drip the colored penetrant into the contour of the surface defect;

[0015] 8) When the surface defect position continuously absorbs the colored penetrant and reaches a saturated state, stop titrating the colored penetrant;

[0016] 9) Calculate the volume V of the colored penetrant dripped into the surface defect;

[0017] 10) According to the formula (Unit: mm) Calculate the depth of surface defects.

[0018] Preferably, the predetermined time in step 2) and step 4) is ten minutes.

[0019] Preferably, the volumetric burette is graduated with a minimum graduation of 0.01 ml.

[0020] Preferably, the colored penetrant has good fluidity and permeability and can effectively penetrate into surface defects.

[0021] Preferably, the colored developer can produce a significant color contrast with the colored penetrant, thereby improving the visibility of the defect.

[0022] Preferably, the line width of the black marker pen does not exceed 1 mm to ensure marking accuracy.

[0023] Preferably, the formula According to the volume formula of a sphere Derived from.

[0024] Preferably, the operation process of dripping the volume V of the penetrant into the defect should not exceed 40 minutes.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention uses a colored penetrant, a colored developer and a black marker pen, and combines a volumetric burette to measure the volume of the colored penetrant, and finally calculates the depth of the defect. The method is simple to operate, has accurate results, and is applicable to cast iron parts of various shapes and sizes. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention provides a flow chart of a method for detecting the depth of surface defects of cast iron parts. DETAILED DESCRIPTION

[0028] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. For example, "including" mentioned throughout the specification and claims is an open term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect.

[0029] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "horizontal", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present application.

[0030] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0031] The following is a further detailed description of a method for detecting the depth of surface defects of a cast iron part of the present application in conjunction with the accompanying drawings, but it is not intended to limit the present application.

[0032] The present invention provides a method for detecting the depth of surface defects of cast iron parts. The present invention can quickly and accurately detect the depth of surface defects of cast iron parts, and in particular, it relates to a method for detecting the depth of surface defects of ductile iron parts, which has low detection cost, is easy to use, and has high detection efficiency.

[0033] In order to study the detection method of the depth of surface defects of cast iron parts, longitudinal and transverse cutting tests were carried out on multiple crankshaft defects to observe the actual distribution of defects and the actual depth of defects. After multiple test analyses, it was found that the actual volume V of the defect infiltrated by the colored penetrant can be used to obtain the defect depth d. According to the longitudinal defect section observation, the defect shape can be idealized as a sphere. According to the volume V formula of the sphere: The formula for calculating the defect depth is: The unit of d is millimeter. The actual defect depth is measured and the defect depth value is calculated by formula theory. Accurate and consistent, the data has been verified to be accurate multiple times.

[0034] like Figure 1 As shown, a method for detecting the depth of surface defects of cast iron parts, the specific steps are as follows:

[0035] 1) Spray the colored penetrant onto the surface defective position of the cast iron parts;

[0036] 2) After the predetermined time, use a clean paper towel to remove the colored penetrant on the surface defects;

[0037] 3) Spray the colored developer evenly on the surface defect location;

[0038] 4) After a predetermined time, the surface defect position displays the defect shape;

[0039] 5) Use a black marker to mark the contour shape of the surface defect;

[0040] 6) Use a clean paper towel to remove the colored developer, leaving the outline of the surface defect marked with a black marker pen;

[0041] 7) Use a volumetric burette filled with colored penetrant to gradually drip the colored penetrant into the contour of the surface defect;

[0042] 8) When the surface defect position continuously absorbs the colored penetrant and reaches a saturated state, stop titrating the colored penetrant;

[0043] 9) Calculate the volume V of the colored penetrant dripped into the surface defect;

[0044] 10) According to the formula (Unit: mm) Calculate the depth of surface defects.

[0045] The predetermined time in step 2) and step 4) is 10 minutes. The volumetric burette has a scale, and the minimum scale is 0.01 ml.

[0046] The colored penetrant should have good fluidity and permeability and be able to effectively penetrate into surface defects. The colored developer and the colored penetrant can be of different colors to produce a clear color contrast, thereby improving the visibility of defects. The color of the colored penetrant is not limited to one color.

[0047] The line width of the black marker pen does not exceed 1 mm to ensure marking accuracy.

[0048] Defect depth value The premise for accurate data is that the operation process of calculating the volume V of colored penetrant dripped into the defect cannot exceed 40 minutes. Repeated verification process shows that the longer the operation process is, the greater the error between the data and the true value.

[0049] The above method is suitable for depth detection of surface defects of cast iron parts of various shapes and sizes.

[0050] The implementation methods of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above implementation methods, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present application.

Claims

1. A method for detecting the depth of surface defects of cast iron parts, characterized in that: The steps include: 1) Spray the colored penetrant onto the surface defective position of the cast iron parts; 2) After the predetermined time, use a clean paper towel to remove the colored penetrant on the surface defects; 3) Spray the developer evenly on the surface defect location; 4) After a predetermined time, the surface defect position displays the defect shape; 5) Use a black marker to mark the contour shape of the surface defect; 6) Use a clean paper towel to remove the developer, leaving the outline of the surface defect marked with a black marker pen; 7) Use a volumetric burette filled with colored penetrant to gradually drip the colored penetrant into the contour of the surface defect; 8) When the surface defect position continuously absorbs the colored penetrant and reaches a saturated state, stop titrating the colored penetrant; 9) Calculate the volume V of the colored penetrant dripped into the surface defect; 10) According to the formula (Unit: mm) Calculate the depth of surface defects.

2. The method for detecting the depth of surface defects of a cast iron part according to claim 1, characterized in that: The predetermined time in step 2) and step 4) is ten minutes.

3. The method for detecting the depth of surface defects of a cast iron part according to claim 1, characterized in that: The volumetric burette is graduated with a minimum graduation of 0.01 ml.

4. The method for detecting the depth of surface defects of a cast iron part according to claim 1, characterized in that: The colored penetrant has good fluidity and permeability and can effectively penetrate into surface defects.

5. The method for detecting the depth of surface defects of a cast iron part according to claim 1, characterized in that: The developer can be a different color from the colored penetrant to produce a significant color contrast, thereby increasing the visibility of defects.

6. The method for detecting the depth of surface defects of a cast iron part according to claim 1, characterized in that: The line width of the black marker pen does not exceed 1 mm to ensure marking accuracy.

7. The method for detecting the depth of surface defects of a cast iron part according to claim 1, characterized in that: The formula According to the volume formula of a sphere Derived from.

8. The method for detecting the depth of surface defects of a cast iron part according to claim 1, characterized in that: The operation process of dripping the volume V of penetrant into the defect should not exceed 40 minutes.

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