Basic operation and precautions of electric welding, types

1. General provisions for arc welding

Motors, electrical appliances and air compressors on welding equipment shall be implemented in accordance with relevant regulations, and complete protective casings shall be provided, and protective covers shall be provided at the primary and secondary terminals.

the electric welding machine used on site should be equipped with a shed that can prevent rain, moisture and sun, and equipped with fire-fighting supplies.

during welding, welding and cooperation personnel must take safety measures to prevent accidents such as electric shock, falling from high altitude, gas poisoning and fire.

it is forbidden to weld and cut the pressure pipes, containers filled with inflammable and explosive articles and stressed members in operation.

When welding nonferrous metals such as copper, aluminum, zinc, tin and lead, it must be carried out in a well-ventilated place, and the welding personnel should wear gas masks or breathing filters.

when welding in the container, the following measures must be taken: the container must have air inlet and outlet and ventilation equipment; The lighting voltage in the container shall not exceed 12V, and someone must be present when welding. It is strictly forbidden to weld in the container with sprayed paint or plastic.

when welding preheating weldments, baffles should be set to isolate the radiant heat emitted by weldments.

when welding or cutting at high altitude, the safety belt must be hung, and fire prevention measures should be taken around and below the weldment, and there should be a special person to monitor it.

when the welding wire passes through the road, it must be elevated or buried underground in the protective pipe. if it passes through the track, it must pass under the track.

the grounding wire and handle wire shall not be placed on inflammable, explosive and articles with heat sources, and the grounding wire shall not be connected to pipes, machine tools, equipment and metal frames or tracks of buildings, and the grounding resistance shall not be greater than 4Ω.

open-air welding is not allowed in rainy days. When working in wet areas, operators should stand in places covered with insulating materials and wear insulating shoes.

when using the electric welding machine that has been stopped for a long time, it is necessary to check that its insulation resistance shall not be less than .5MΩ, and the wiring part shall not be corroded and damp.

the electrode holder should be firmly connected with the handle wire, and the electrode holder should not be held by the arm. When removing welding slag, the face should avoid the cleaned weld.

during the load operation, the welder should always check the temperature rise of the electric welding machine. If it exceeds 6°C of Class A and 8°C of Class B, it must stop the operation and cool down.

flammable materials such as oxygen cylinders, acetylene generators and wood shall not be stacked within 1m of the welding site.

after the operation, clean up the site, extinguish the fire, cut off the power supply, lock the switch box and eliminate the residual heat of solder before leaving.

2. AC welding machine

Attention should be paid to the primary and secondary wires, and the input voltage must conform to the nameplate of the welding machine. It is forbidden to touch the live part of the primary circuit.

the secondary tap connection copper plate must be pressed tightly, and the terminal should have a gasket. Check the wiring nuts, bolts and other parts in detail before closing, and see if they are loose or damaged.

when moving the welding machine, the power supply should be cut off, and the welding machine should not be moved by dragging cables. In case of sudden power failure during welding, the power supply should be cut off.

3 butt welding machine

The butt welding machine should be installed indoors and have reliable grounding (zero connection). If several butt welding machines are installed side by side, the spacing shall not be less than 3m.

Before operation, check that the pressure mechanism of the butt welding machine should be flexible, the fixture should be firm, and there is no leakage in the gas and hydraulic systems. Only after it is confirmed to be normal can welding be carried out.

before welding, the secondary voltage should be adjusted according to the cross section of the welded steel bar, and the steel bar with a diameter exceeding that specified by the butt welder should not be welded.

the contact points and electrodes of the circuit breaker should be polished regularly, and all the connecting bolts of the secondary circuit should be tightened regularly. The cooling water temperature shall not exceed 4°C；; The displacement should be adjusted according to the temperature.

when welding long steel bars, brackets should be set. Cooperate with the operators who carry steel bars, and pay attention to prevent spark burns during welding.

a baffle should be set in the flash area, and irrelevant personnel are not allowed to enter during welding.

during winter construction, the indoor temperature should not be lower than 8 C .. After operation, drain the cooling water in the machine.

4. Electroslag pressure welding machine

1. The welding machine must be grounded to ensure the safety of operators, and the welding wires should be reliably insulated.

2. Welders must wear protective clothing. When welding, the welder should stand on a dry wooden mat or other insulating mat.

3. In the process of welding, if the welder makes abnormal noise, it should be checked immediately.

4. A voltmeter is installed in the power switch box of the welder to facilitate observation of voltage fluctuation. If the voltage drop of the power supply is greater than 5%, it is not suitable for welding.

5. BX2-1 welding transformer should be adopted. It can also be used in parallel with welding transformers of the same model with smaller capacity.

6. A voltmeter, a power meter and a signal bell should be installed in the control box, which is convenient for the operator to control the welding parameters and correctly grasp the welding power-on time.

3. Safety operation procedures for chainsaws and planers

1. Before band sawing machine

operation, check the saw blade. If the crack length on the tooth side of the saw blade exceeds 1mm, the crack length at the joint of the saw blade exceeds 1mm, and the saw blade with two consecutive missing teeth and more than three joints shall not be used. Cracks must be punched with a crack stop hole at the crack terminal within the above provisions. After the tightness of the saw blade is properly adjusted, it should be run without load. If the sound is normal and there is no string phenomenon, it can be operated.

during operation, the operator should stand on both sides of the band saw. After the sports car starts, no one is allowed to stand around the track within the travel range, and it is forbidden to get on or off the sports car during operation.

logs should be adjusted in size before sawing, but not after sawing. The sawing speed is even, not too fast.

only after the tail end of the wood crosses the saw blade for .5m can the March be reversed. The reversing speed should not be too fast, so pay attention to the wood if the knot scar touches the saw blade.

during the platform band saw operation, the feeding and receiving materials should be coordinated. When feeding and receiving materials, hands shall not be sent to the table. When sawing short materials, push rod should be used to feed. When sending back the wood, leave the saw blade more than 5mm, and pay attention to the wood if the joint scar touches the saw blade.

When the band saw equipped with pneumatic dust suction hood blocks the dust suction nozzle, it is forbidden to clean the nozzle on the back side of the saw wheel with a wooden stick during operation.

the weight (heavy hammer) of the tensioning device of the sawing machine should be adjusted according to the width and thickness of the saw blade, or the auxiliary weight should be increased or decreased. It is not allowed to overcome the phenomenon of loose mouth or stringing of the saw blade by increasing the weight of the heavy hammer.

2. Disc saw

A safety baffle and a dripping device must be installed above the saw blade, and an arc wedge knife must be installed behind the saw blade at a distance of 1~15mm from the teeth. The saw blade shall be installed concentrically with the shaft.

the saw blade must have sharp teeth, and two teeth shall not be missing continuously, and the crack length shall not exceed 2mm, and the crack shall be stopped at the end of the crack.

the thickness of the sawn wood is limited to 1~2mm, and the diameter of the flange for clamping the saw blade should be 1/4 of the diameter of the saw blade.

after start-up, sawing can only be carried out after the speed is normal. When feeding, do not shake or lift the wood from side to side, and feed slowly when encountering knots. The sawing length should be not less than 5mm. When approaching the end, push rod should be used to feed.

if the saw wire deviates, it should be corrected gradually, and it is not allowed to pull it violently to avoid damaging the saw blade.

the operator shall not stand on the surface of the rotating centrifugal force of the saw blade to operate, and his hands shall not cross the saw blade.

when the temperature of the saw blade is too high, it should be cooled by water. Saw blades with a diameter of more than 6mm should be cooled by spraying water during operation.

3. Plane planing (hand planing)

Before operation, check that the safety protection devices must be complete and effective.

when planing, keep your hands on the top of the material, and your fingers must be more than 5mm away from the plane. It is forbidden to feed the wood at the back end by hand and plane it across the plane.

when the thickness of the planed wood is less than 3mm and the length is less than 4mm, it should be pushed by pressing plate or stick. Wood with a thickness of 15mm and a length of less than 25mm shall not be processed on a planer.

if the planed wood has defects such as cracks or knots, it must be treated before planing. Before planing the old material, the nails and sundries on the material must be removed. In case of wood bumps and knots, feed slowly. It is forbidden to press your hand on the knot scar to feed.

the thickness and weight of the blade and the blade screw must be the same, the tool holder splint must be flat and tight, the weld height of the alloy blade should not exceed the tool head, the blade fastening screw should be embedded in the blade groove, and the groove end should not be less than 1mm away from the back of the blade. When tightening the blade screws, the force should be uniform and not too loose or too tight.

when the machine is running, it is forbidden to put your hand into the inside of the safety baffle to move the baffle or remove the safety baffle for planing. It is forbidden to operate with gloves.

4. planer (single-sided and multi-sided)

planer must use one-way switch, and reverse switch is not allowed. Planers on three or four sides should be started in sequence.

during operation, it is forbidden to plane two pieces of wood with different materials and specifications at a time, and the thickness of the planed wood shall not exceed 5 mm. The operator should stand on one side of the machine tool, do not wear gloves when receiving and feeding, and must be advanced when feeding.

the horizontal clearance between the planer and the planer table should be 1~3mm, the screws of the planer must be of equal weight, and the force should be uniform when fastening, and it is forbidden to use a planer with an open slot.

the feed rate should be 2~5mm each time. in case of hardwood or scab, the feed rate should be reduced and the feeding speed should be reduced.

the length of the planer shall not be shorter than the center distance of the front and rear rollers, and the thin plate with the thickness less than 1mm must be supported.

the planer must be equipped with a rebound-sensitive backstop device, and the feeding toothed roller and the material-supporting smooth roller should be adjusted horizontally and at the same distance from top to bottom. The toothed roller should be 1~2mm lower than the surface of the workpiece, and the smooth roller should be .3~.8mm higher than the table top, and the table top should not be skewed and uneven.

Precautions for installing blades shall be implemented according to Article 5 of the plane planer.

iv. Rules for safe operation of steel bar processing machinery

(I) General provisions

1. Steel bar processing machinery powered by motor and hydraulic pressure and assisted by hoist shall be implemented in accordance with relevant regulations.

2. The installation of machinery must be solid and stable, and keep the horizontal position. Stationary machinery should have a reliable foundation, and mobile machinery should wedge the walking wheels when working.

3. For outdoor operation, a hangar should be set up, and there should be a place for stacking raw materials and semi-finished products beside the hangar.

4. When processing a long steel bar, there should be a special person to help, and follow the instructions of the operator, and it is not allowed to push or pull at will.

5. After the operation, the finished products should be piled up. Clean up the site, cut off the power supply and lock the switch box.

(II) Steel bar straightening and cutting machine

1. The material rack and trough should be installed straight and aligned with the center lines of the guide cylinder, straightening cylinder and lower cutter hole.

2. Turn the flywheel by hand, check the transmission mechanism and working device, adjust the clearance, tighten the bolts, and start the idle running after confirming that it is normal. Check that the bearing should have no abnormal sound and the gears are well engaged. Only after the operation is normal can the operation be started.

3. according to the diameter of the straightening steel bar, select the appropriate straightening block and transmission speed. After debugging, the material can be fed.

4. No feeding is allowed before the straightening block is fixed and the protective cover is not covered. It is forbidden to open the protective covers of each part and adjust the gap during operation.

5. When the steel bar is sent in, the hand must keep a certain distance from the traction sheave, and shall not approach.

6. Before feeding, the material head that is not straight should be cut off, and a 1m-long steel pipe should be installed in front of the guide cylinder. The steel bar must first pass through the steel pipe and then be sent into the guide hole at the front end of straightening.

7. after the operation, the straightening block of the straightening cylinder should be loosened and returned to its original position, and the preloading spring must be returned.

(3) steel bar cutting machine

1. The material receiving and delivering workbench should be level with the lower part of the cutter, and the length of the workbench can be determined according to the length of the processed material.

2. Before starting, it must be checked that the cutter should be free of cracks, the tool holder bolts should be fastened and the protective cover should be secure. Then turn the pulley by hand, check the gear meshing clearance and adjust the cutter clearance.

3. After starting, run in idle mode first, and check that all transmission parts and bearings are operating normally before operation.

4. when the machine does not reach the normal speed, it is not allowed to cut the material. When cutting materials, the middle and lower parts of the cutter must be used, and the steel bars should be gripped and aligned with the cutting edge to feed them quickly.

5. The rebar and red-hot rebar whose diameter and strength exceed those specified in the mechanical nameplate shall not be cut. When cutting more than one steel bar at a time, the total cross-sectional area should be within the specified range.

6. when shearing low-alloy steel, a high-hardness cutter should be replaced, and the diameter should meet the requirements of the nameplate.

7. When cutting short materials, the distance between the hand and the cutter should be kept above 15 mm. If the hand-held end is less than 4mm, the short end of the steel bar should be pressed or clamped firmly with a sleeve or clamp.

8. During operation, it is forbidden to directly remove the broken ends and sundries near the cutter by hand. Non-operators are not allowed to stay around the steel bar swing and the cutter.

9. If abnormal mechanical operation, abnormal sound or skewed cutter are found, stop the machine immediately for maintenance.

1. after the operation, remove the sundries between the cutters with a steel brush, and clean and maintain the whole machine.

(4) steel bar bender

1. The workbench and the table top of the bender should be kept level, and all kinds of mandrels and tools should be prepared.

2. Install the mandrel, forming shaft, iron retaining shaft or variable retaining frame according to the requirements of the diameter and bending radius of the processed steel bar, and the diameter of the mandrel should be 2.5 times of the diameter of the steel bar.

3. check that the mandrel, stopper and turntable should be free of damage and cracks, and the protective cover should be fastened reliably. Only after the idle operation is confirmed to be normal can the operation be started.

4. During operation, insert one end of the steel bar to be bent into the clearance of the fixed pin of the turntable, and the other end is close to the fixed pin of the fuselage, and press it by hand. Check that the fixed pin of the fuselage is really installed on the side blocking the steel bar before starting.

5. During the operation, it is forbidden to change the mandrel and pin, change the angle and adjust the speed, and it is also forbidden to refuel or clean.

6. When bending steel bars, it is forbidden to exceed the diameter, number and mechanical speed of steel bars specified by this machine.

7. when bending high-strength or low-alloy steel bars, the maximum limiting diameter should be converted according to the provisions of the mechanical nameplate and the corresponding mandrel should be replaced.

8. It is forbidden to stand within the working radius of bending steel bars and on the side of the fuselage without fixing pins. The bent semi-finished products shall be neatly stacked, and the hooks shall not face upwards.

9. When the turntable is reversed, it must be stopped.

(V) Cold-drawn machine for steel bars

1. According to the diameter of cold-drawn steel bars, the winch is selected reasonably, and the hoisting wire rope should pass through the closed guide pulley and be at right angles to the direction of the drawn steel bars. The position of the hoist must enable the operator to see all the cold-drawn sites, with a distance of not less than 5m from the cold-drawn center line.

2. The cold-drawn site shall be provided with a warning zone outside the ground anchors at both ends, with protective railings and warning signs. Irrelevant personnel are strictly forbidden to stay here. Operators must leave the rebar at least 2m away during operation.

3. The equipment controlled by counterweight must match the pulley, and be marked to indicate the rise and fall. If there is no indication mark, there should be a special person to direct it. When lifting the counterweight frame, the height should be limited to 3mm from the ground, and there should be railings and warning signs around the counterweight frame.

4. Before operation, check the cold-drawn fixture, the clamping teeth must be in good condition, the pulley and towing trolley should be lubricated flexibly, and the retractor, ground anchor and protective device should be complete and firm. Only after confirmation is good can operation be started.

5. The hoist operator must see the signal from the commander and wait for all personnel to leave the danger zone before working. Cold drawing should be carried out slowly and evenly. Pay attention to the stop signal at any time or stop drawing immediately when someone enters the danger zone, and slightly relax the hoisting wire rope.

6. devices controlled by elongation must be equipped with obvious limit signs, and there should be a special command.

7. Lighting facilities for night work should be located outside the tension danger zone. If it must be installed above the site, its height should be more than 5m. The light bulb should be protected with a protective cover, and bare wires are not allowed.

8. after operation, loosen the hoisting wire rope, drop the counterweight, cut off the power supply and lock the electricity.