Introduction: Cylinder dryer quality control equipment manufacturing supervision
A cylinder dryer is the most widely used drying equipment in industrial drying equipment. It is used in mineral processing, building materials, metallurgy, chemical industry, and other industries to dry materials with a certain humidity or particle size, including slag, fly ash, and sawdust, coal slime, desulfurized gypsum, compound fertilizer, food, etc. It is characterized by high productivity and easy operation.
The cylinder of the drum dryer is a horizontal rotary cylinder. Various lifting plates with staggered arrangements at different angles are welded inside from front to back. The dryer rotates to make the material flow in the cylinder in a predetermined direction and form. The hot air sent in performs heat exchange to evaporate the water to achieve the drying effect.
Hot air can be produced by the combustion of coal, heavy oil, natural gas, and other fuels, or it can be waste heat waste gas produced by other processes. The ZJTL series downstream rotary dryer exported by TONGLI is φ2.4×18m for drying slag. The maximum designed capacity is to dry 60 tons of wet slag with a water content of 10% per hour to a moisture content of 1 to 3%. To realize the continuous and stable operation of the dryer, the quality control of the equipment, that is, equipment manufacturing supervision, has been strengthened. The specific contents are as follows:
1 Inspection and flaw detection of slag dryer shell cylinder
First conduct a chemical analysis and inspection of the material. By the requirements of GB700-2006, the material with a thickness of 20mm is Q235-B; by GB/T 2970-2004 Level II, ultrasonic flaw detection is performed on the 60mm range of the weld edge of each plate before cutting.
When cutting the rolled plate, in addition to checking the size, ultrasonic flaw detection is performed on the cutting edge of each plate within 60mm according to GB/T 2970-2004 Level II.
Welding, the tailings dryer barrel segments should be circumferentially welded. The number of longitudinal welds along the entire circumference should not be more than two, the barrel welds should be full, and the minimum weld should not be lower than the base metal. The surface should be no higher than 3mm, and the welds at the lifting plate should be smoothed. The depth of the weld undercut should not be greater than 0.5mm, the continuous length should not be greater than 100mm, and the total length of each weld undercut should not exceed 10% of the length of the weld. Conduct ultrasonic flaw testing and magnetic particle testing on longitudinal and circumferential welds.
The ultrasonic testing is by GB/T 11345 II Level B (excluding the entrance flange), and the magnetic particle testing is by JB/T 4730-2005 Level II, and by 25%/100 % principle, that is, if a defect is found in 25% range testing, it needs to be extended to 100% testing.
After assembly, the main dimensional inspection is carried out according to the drawings.
2 Mechanics and inspection of slag dryer riding ring/tyre
Casting is carried out after mold inspection, and chemical analysis and mechanical testing of the castings are carried out by GB11352-1989 requires materials no less than ZG310-570.
Rough machining, check dimensions according to drawings and conduct ultrasonic flaw detection according to standard GB/T7233-87 Level II. Repair welding of surface defective parts. The restrictions for repair welding are: the maximum size of a single defect is 5% of the working width, the maximum depth of the defect is 5mm, the maximum total defect area is 2% of the processed surface, and the number of defect points on the entire surface is less than 5 (Before welding, a welding plan should be submitted, including preheat treatment and immediate heat treatment, as well as a defect location report.
The repair work needs to be recorded, and the difference in hardness between the repair area and the original area should be checked to ensure that the repair area The appropriate hardness, the hardness difference is less than 20HB). No cracks are allowed in the repair area. Ultrasonic flaw detection shall be carried out by GB7233-87 Level II. Magnetic particle flaw detection shall be carried out by JB/T5000.14-1998 Quality Level 1. JB/T5000.14-1998 Quality Level 1 shall be carried out with dye penetration.
For final finishing, in addition to checking the dimensions, conduct a hardness test (the hardness difference is less than 40HB). According to the requirements of JC/T333-2006, no cracks are allowed. Magnetic particle inspection should be carried out according to JB/T5000.14-1998 quality level 1. Refer to JB/T5000.14-1998 quality level 1 for dye penetration.
3 Flaw detection and inspection of the supporting wheel of the water slag dryer
Casting, chemical analysis, and mechanical testing, according to JC/T 401.2-1996 material standard, shall not be lower than ZG340-640.
Normalizing treatment, the hardness of the outer surface of the supporting wheel after processing should not be less than 190HB.
Rough machining, perform ultrasonic flaw detection on the processed surface, refer to the standard GB/T7233-87level III, the thickness of the outer layer of the processed surface should be 10mm, and the other parts should be inner layers. Repair welding of surface defective parts. The restrictions for repair welding are: the maximum size of a single defect is 5% of the working width, the maximum depth of the defect is 5mm, the maximum total defect area is 2% of the processed surface, and the number of defect points on the entire surface is less than 5 (Before welding, a welding plan should be submitted, including preheat treatment and immediate heat treatment, as well as a defect location report.
The repair work needs to be recorded, and the difference in hardness between the repair area and the original area should be checked to ensure that the repair area The appropriate hardness, the hardness difference is less than 20HB). No cracks are allowed in the repair area. Ultrasonic flaw detection shall be carried out by GB7233-87 Level II, magnetic particle flaw detection shall be carried out following JB/T5000.14-1998 Quality Level 1, and dye penetration shall be carried out under JB/T5000.14-1998 Quality Level 1.
Final finishing, roughness test, magnetic particle inspection according to JB/T5000.14-1998 quality level 1, cracks are not allowed, hardness >= HB190, hardness difference less than 40HB.
Assemble, check relevant dimensions, and wait for packaging after anti-rust treatment.
4 High-efficiency slag drying equipment large ring gear production process
Casting shall be carried out after mold inspection, and the material shall not be lower than the requirements of ZG310-570 in JC/T 401.2-1996.
Castings should be normalized, and the hardness should refer to the drawings/ordering specifications or HB190-230.
Rough machining, check the dimensions according to the drawings, the entire working tooth part and the connecting hole area shall be subjected to ultrasonic flaw detection following the standard GB/T7233-87 Level II, and other parts shall be carried out per the standard GB/T7233-87 Level III. Magnetic particle flaw detection/fuel penetration shall be carried out by the standard. JB/T5000.14-1998 quality level 1, no cracks allowed. Repair welding of defective parts of the surface. Restrictions for repair welding: the maximum size of a single defect shall not exceed 5% of the working width, the maximum depth of the defect shall be 5 mm, and the maximum total defect area shall be 2% of the processed surface.
On the entire surface, the defect point is Less than 5, please note that repair welding is not allowed in the entire working tooth area (before welding, a welding plan should be submitted, preheating treatment and instant heat treatment should be carried out, and a defect location report should also be provided. The repair work needs to be recorded, examine the difference in hardness between the repaired area and the original area, thus ensuring the proper hardness of the repaired area. The hardness difference is less than 20HB. ) No cracks are allowed in the repair area. Ultrasonic flaw detection shall be carried out by GB7233-87 Level II, magnetic particle flaw detection shall be carried out following JB/T5000.14-1998 Quality Level 1, and dye penetration shall be carried out per JB/T5000.14-1998 Quality Level 1.
For final finishing, in addition to checking the dimensions, conduct a hardness test (the hardness difference is less than 40HB). According to the requirements of JC/T333-2006, no cracks are allowed. Magnetic particle inspection should be carried out per JB/T5000.14-1998 quality level 1. Refer to JB/T5000.14-1998 quality level 1 for dye penetration.
5 Manufacturing of pinions and shafts for high-output slag dryers
Forging of the pinion gear and its shaft, chemical analysis, and mechanical testing of materials, refer to JB/T6397-92, the material standard shall not be lower than 45# steel.
Pre-processing and ultrasonic flaw detection, refer to JB/T5000.15-1998 level II standard.
The surface hardness of the tooth top circle after quenching and tempering treatment should not be less than 220HB.
Final finishing, mechanical hardness test refers to the drawing, and magnetic particle inspection is performed. There are no cracks on the pinion. The roughness test requires that the roughness Ra of the machined surface of the pinion bearing should be less than 3.2.
Assemble the shaft and check the dimensions.
6 roller bearings
Material inspection, including dimensions and magnetic particle inspection concerning JB/T5000.14-1998 grade 01 quality standards.
Assemble according to the drawings and check relevant dimensions.
7 Gear wheel and gear shaft
The gear wheel and gear shaft are poured, and the materials are chemically analyzed. The gear wheel shall refer to GB11352-1989 material standard and shall not be lower than ZG340-640, and the gear shaft requirements shall refer to GB/T11352-1989.
The gear shaft is forged, and material analysis and mechanical testing are carried out per the standard JB/T6397-92 to make it meet the relevant requirements.
With assembly, the ultrasonic flaw detection of the shaft refers to JB/T5000.15-1998 Level II standard and the ultrasonic flaw detection of the blocking wheel Refer to GB/T7233-87 Level II standard.
Normalizing treatment should be carried out, and the cone’s working surface will be hard after processing.The temperature should not be lower than 190HB.
Final finishing.
Problems found during dryer quality inspection and how to deal with them:
The cylinder welds have missing welds, etc. After rectification, the Require;
Ultrasonic flaw detection and surface hardness inspection of the tire belt, supporting roller, and blocking wheel found that the grains were too large, the hardness value was too small, and the heat treatment was incomplete. They were replaced and reprocessed by the outsourcing factory to meet the requirements;
Pinion seat If there are blisters, repair the casting by welding;
The cone angle of the gear wheel and the wheel belt is inconsistent, and the gear wheel support must be reprocessed to achieve Same cone angle;
The public normal line of the large gear does not match the design drawing after measurement and must be reprocessed to make it consistent.
After checking the drawings, it was found that the block on the cylinder body that fixes the position of the wheel belt interferes with the blocking wheel. It is required to modify the design and make parts according to the new drawings to eliminate hidden dangers.
Summarize:
Quality control should start from the source. The raw materials entering the factory need to be re-inspected. Pay attention to the heat treatment process of the selected outsourcing blank factory. If the requirements are not met, the processed parts will not meet the quality requirements. Each equipment part of the dryer has hardness requirements, and the hardness value needs to be rechecked after heat treatment and finishing. Non-flaw detection is the key, requiring inspection personnel to have corresponding qualifications. If the manufacturer does not have the qualifications, external personnel should be seconded.
The quality inspection department needs to review the design drawings, especially the common normal of the gear must meet the design requirements. Only by strictly following the relevant requirements and carefully inspecting each node can we find and solve problems on time and provide users with products of trustworthy quality.
