Some standard content:
Machinery Industry Standards of the People's Republic of China
Method for assessment of appearance quality of brazed seams
Subject content and scope of application
1
This standard specifies the assessment method of appearance quality of seams. This standard is applicable to the inspection and evaluation of the appearance quality of brazed joints. 2 Reference standards
GB5616 Guidelines for the application of conventional non-destructive testing
GBJ94 Specifications for construction and acceptance of spherical storage tanks
ZBH04005 Penetration flaw detection method
3 terminology
JB /T 6966-93
3.1 Brazing seam
The bonding area (see Figure 1) formed by the solidification of liquid metal in the brazing joint is called the brazing seam. In lap joints or T-joints, the braze seam usually includes a braze fillet.
Needle fillet
Braze fillet
Needle seam
Lap joint
bT-shaped joint
Figure 1 Brazing Joint
3.2 Brazed fillet
Needle welded fillet
Brazed seam
Butt joint
Over lap joint T-shaped joint (see picture 1a, 1b) During needle welding, the fillet fillet formed by the filler metal overflowing from the gap outside the brazing seam is part of the brazing seam.
3.3 Not full
A brazing defect caused by excessive loss of molten solder or insufficient quantity to fill the solder gap, see Figure 2. Not full
Picture 2 Not full
Approved by the Ministry of Machinery Industry of the People's Republic of China on 1993-07-27 Not full
Implemented on 1994-07-01
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4 General requirements
4.1 Inspection parts
JB/T6966-
All exposed seam surfaces are subject to appearance quality inspection. 4.2 Surface cleaning
93
Before inspecting the appearance quality of the brazing joint, foreign inclusions such as oil, oxides, flow inhibitors and flux residues at the brazing joint to be inspected should be thoroughly removed. 4.3 Inspection personnel
Inspection personnel should be trained and should be able to make correct judgments on the degree of appearance defects of needle-brazed seams. 5 Appearance quality assessment of stitching
5.1 Appearance quality of stitching is mainly assessed by visual inspection (including using a magnifying glass below 10 times). When necessary, coloring inspection methods and sealing inspection methods can be used.
5.2 The appearance quality of brazing seams is divided into 1, I, and I levels. Class 5.2.11 brazing seam
is suitable for brazing parts that bear large static load, dynamic load or alternating load, or have high requirements for air tightness and decorative appearance of the brazing seam. The surface of the brazing seam is continuous and dense, the welding angle is smooth and even, and it shows an obvious concave arc transition. Cracks, pinholes, pores, looseness, knots and corrosion spots are not allowed on the surface. The needle material has no visible pitting corrosion on the base metal. Class 5.2.21 brazing seam
is suitable for welding parts that bear moderate static load, dynamic load or alternating load, or have certain requirements for the air tightness and decorative appearance of the brazing seam. The stitches are all soldered and the welding angles are continuous, but the uniformity is poor. There are a small number of slight scattered pores, looseness and corrosion spots on the surface of the brazing joint, but cracks and pinholes are not allowed. The brazing material has visible concave corrosion on the base metal, but its depth does not exceed 5% to 10% of the thickness of the base metal. This should be determined based on the thickness of the brazing component at that location and its working conditions. 5.2.3 grade brazing seam
is suitable for brazing parts that bear a small static load, or have low requirements on the air tightness and decorative appearance of the brazing seam. The brazing seams are poorly formed, the seams are discontinuous, not smooth and evenly hooked, there are partial imperfections and pores, and relatively dense looseness, but cracks, penetrating pores, and pinholes are not allowed. The solder is allowed to have obvious concave corrosion on the base metal, but its depth is not greater than 10% to 20% of the thickness of the base metal at that location, and should be determined based on the working conditions of the component.
5.3 Defect treatment of brazed parts
There are cracks, penetrating pores, pinholes, and pores that do not comply with the product drawings, shrinkage, corrosion, incomplete brazing and surface roughness on the surface of the brazing seam , should be repaired or scrapped according to the product drawing requirements. The frequency of repair brazing should be determined according to the type of base metal and the working conditions of the component. 6 Inspection method for appearance quality of brazing seams
6.1 Visual inspection method
6.1.1 Observe and inspect with naked eyes. Suitable for obvious visible macro defects. 6.1.2 Magnifying glass inspection. Use a magnifying glass not exceeding 10 times for inspection, which is suitable for surface defects that are difficult to distinguish with the naked eye, such as tiny cracks, pores, and corrosion.
6.1.3 Reflector inspection. It is suitable for deep holes, blind holes and other occasions where direct visual inspection is not possible (see Figure 3). If necessary, a 3~~10x magnifying glass can be used for visual observation.
6.1.4 Endoscopy. Mainly used for inspection of surface brazing seams in curved or blocked parts (see Figure 4). If necessary, a 3 to 10 times magnifying glass can be used for observation.
Visual inspection can identify macroscopic defects such as the shape of the stitches, surface cracks, pores, shrinkage, incomplete stitches, corrosion, knots, pinholes, surface roughness of the stitches, and corrosion spots||tt ||314
Reflector
Light source
JB/T 6966-
Check the pin angle here
93
Optical fiber www.bzxz.net
Check the angle here
7227727Z
Figure 3 Schematic diagram of reflector inspection of deep hole components 6.2 Penetrant inspection method
Figure 4 Schematic diagram of endoscopic inspection of curved components It is suitable for appearance inspection of level 1 and level 1 brazing seams to determine whether there are tiny cracks, pores, pinholes and other defects on the surface of the brazing seam that are difficult to distinguish with the naked eye. Inspection can be carried out according to the relevant regulations in GB5616 and ZBH04005. Small workpieces are generally inspected by fluorescence inspection, and large workpieces are usually inspected by coloring flaw detection.
6.3 Sealing inspection
If the surface of the container's brazing seam is not suitable for visual or penetrant inspection, the sealing inspection can be carried out according to the relevant provisions of GBJ94 to find out the defective parts.
6.3.1 Close all openings of the assembly, then inflate the inner cavity of the brazing container (the inflation pressure is specified in the product drawing), then put it into the water, wait for 1 to 2 minutes, and observe the external brazing seam. Are there any bubbles produced? 6.3.2 Close all openings of the assembly, inflate the inner cavity of the brazing container (the inflation pressure is specified in the product drawing), apply soapy water solution on the outer surface of the brazing joint, and observe whether bubbles appear. 6.3.3 Apply chalk powder to the outer surface of the needle brazing seam, then pour kerosene into the brazing container, wait 5 to 10 minutes, and observe the discoloration of the chalk powder. If oil marks appear on the chalk-coated side, that area is judged to be a defective area. If leakage is found at the soldering joint during the sealing inspection, it must be repaired and the number of repairs and scrapping should be carried out according to the product drawings. 6.4 Record of inspection results
Record the inspection results. The type, location, size, quantity and assessment level of defects must be indicated on the record paper. Additional instructions:
This standard is recommended by Erbin Welding of the Ministry of Machinery Industry. Research institute proposed and centralized. This standard is drafted by the 703 Institute of the Ministry of Aeronautics and Astronautics and Xi'an Aerospace Engine Company. The main drafters of this standard are Qiu Huizhong and Ren Yaowen. 315
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