Skills training paper 1

1 welding theory and practice training requirements

1. 1 welding theory requirements

According to the national vocational qualification regulations, training junior, middle and senior welders requires no less than 280, 320 and 240 standard hours, and technicians and senior technicians no less than 200 standard hours. Training requirements for senior welders.

1.2 welding training requirements

There are many difficulties in learning and mastering welding technology: the teacher (master) explains the main points of welding technology operation and teaches students to operate according to the main points. The teacher corrects the students' deviation, and the students practice the teacher's constant correction repeatedly to meet the teacher's requirements. In the welding learning process, when students are new to welding, they are driven by curiosity and make rapid progress, entering the "T 1- entry period"; But after a period of time, with the improvement of welding technical requirements, the level will not improve, but will decline, entering the "T2- wandering period"; After repeated welding practice, consolidation and improvement, from imitation to proficiency, although there are also failures, repeated attempts will become more mature, and the ability of continuous exploration and innovation will be enhanced, entering the "T3- improvement period". Welding needs to master the angle, speed, arc length, welding parameters (current, voltage, etc. ), the weld groove form, height and width of the joint should also be treated to avoid welding defects such as slag inclusion, porosity and undercut. If the welding is not good, it is necessary to check the welding current and voltage, covered electrode or welding gun angle, welding arc length, weld pool shape, forward speed and stop time on both sides. Therefore, many requirements are often ignored and difficult to master. The only solution is to practice more, observe more and summarize more. Practice makes perfect, and success comes naturally.

2 Implement skill tests

Skills examination can be carried out by means of flat welding, vertical welding, horizontal welding and overhead welding, horizontal fixed welding, vertical fixed welding of pipe and tubesheet specimens, and full penetration T-shaped vertical fillet welding. The senior welder's examination is the transverse fixed welding of 5G (covered electrode SMAW) pipe butt joint, as shown in Figure 3; Test requirements; Scoring standard. The welding equipment is ZX5-400 rectifier welder, and the covered electrode model is E 5015. ; Specifications are 2.5mm and Ф ф3.2mm, when welding, improper selection of operation methods and process parameters will easily lead to welding defects such as cracks, blowholes, slag inclusion, undercut, welding burr and weld deviation, which will seriously affect the weld quality. Cracks on the weld surface, changing the welding position, burning on the pipe surface, missing welding and welding time exceeding 30% of the quota will be directly unqualified. The weld is formed evenly and straightly, and the appearance (front and back) of the weld with the same height, width and width is qualified. After careful practical training, all students can meet the qualification requirements.

3. Check before welding to ensure safe production.

When welding, arc and molten pool will become the paths of thermoelectromagnetism and light, mainly including electric shock, arc radiation, noise, smoke and toxic gas, which directly endanger people's physical and mental health, so the welding site should be well ventilated to reduce the invasion of toxic gas and smoke; Before welding, wear labor protection articles and protective masks to avoid electric arc burning the skin; Protect your eyes, keep them dry and insulated to prevent electric shock. Check whether the rated voltage of the welding machine matches the power supply voltage; Check whether the welding shell is well grounded, whether the internal joints are loose and whether there are metal sundries; Check whether the primary and secondary windings of electric welding machine are in good condition; When closing, avoid electric arc; After closing, if the welder has abnormal sound or arc light, turn on the switch immediately; Check whether there are inflammable and explosive articles around the welding; Prepare fire fighting equipment; Pick up the primary line and switch; When working and resting, the switch should be pulled down and the fixture should be placed in an insulated place; After completion, it is necessary to turn off the switch, cut off the power supply and set up the line in time.

4 conclusion

Welding practice teaching needs a lot of welding materials such as steel plate, steel pipe, covered electrode, welding wire and gas, which consumes a lot of electricity and has strong welding operation skills. In order to ensure the teaching quality, theoretical courses and practical courses must reach 30% and 70%, and the training cost is much higher than other majors. Most students in higher vocational colleges are not good at welding, but enterprises need highly skilled welding talents. Through systematic training, local enterprises can use various welding methods to weld various materials, master welding skills skillfully, realize standardized operation and ensure safe production.