How to keep the welding wire better?
In order to ensure the quality of the welding structure, in addition to the correct selection of welding materials, attention must also be paid to the storage and quality management of welding materials during welding construction.
Welding wire is a kind of metal product, although most of the surface of solid-core welding wire and seamless flux-core welding wire are treated with copper plating, and some of the surface of seam flux-core welding wire are also treated with antirust treatment (such as chemical blackening treatment). In the packing of welding wire, in addition to plastic bags, some bags also add a small bag of moisture-proof agent, and there is a carton packing outside, but moisture-proof is still a problem that must be considered in the storage of welding wire. Because the moisture-absorbing welding wire can increase the content of diffused hydrogen in the deposited metal, resulting in defects such as pits and air holes. The welding process performance and the mechanical properties of the weld metal will be worse, which will seriously lead to the crack of the weld, this is the same as other welding materials. Of course, because the powder in the flux-cored wire is tightly wrapped in the steel belt, the flux-cored powder has little contact with the air, and at the same time, the moisture-absorbing substance like the water glass in the electrode is not used, therefore, compared with the welding rod, the moisture absorption is very small, but if it is placed in high temperature and humidity environment for a long time, it will absorb moisture in addition to rust on the surface of the welding wire. With the increase of moisture absorption time and moisture absorption, the amount of diffused hydrogen in the deposited metal gradually increases, which is unfavorable to the crack resistance of welding seam.
1. Storage requirements of welding wire
① it is required that under the recommended storage conditions, the original welding wire without opening the package can be kept “fresh in the factory” for at least 12 months. Of course, the maximum storage time depends on the surrounding atmospheric environment (temperature, humidity, etc.). Storage conditions recommended by the warehouse: The room temperature is above 10 ~ 15℃ (the highest 40℃), and the maximum relative humidity is 60%.
② the welding wire should be stored in the dry and well-ventilated warehouse, and it is not allowed to be stored in the open air or in the room with harmful gas and corrosive medium (such as SO2, etc.). The room should be kept clean and tidy. When piling up, it is not suitable to put it directly on the ground. It is better to put it on the shelf or pad which is not less than 250mm away from the ground and the wall to keep the air flowing and prevent moisture.
③ because there are many applicable welding methods and steel grades for welding wire, the shapes and packing states of welding wire rolls are also various. According to the difference of the wire feeding machine, the shape of the roll can be divided into plate shape, bundle shape and barrel shape. Therefore, in the process of handling, it is necessary to avoid littering to prevent the packaging from being damaged. Once the package is damaged, it may cause moisture absorption and rust of the welding wire.
As for the bundled welding wire, it is necessary to prevent the deformation of the steel frame and not put it into the wire feeding machine.
For the cylindrical welding wire, do not roll when carrying, and the container should not be laid down or tilted, in case the welding wire in the cylinder is twined and obstructs the use.
2. Management of welding wire in use
① The welding wire should be used up within 1-2 days after unpacking.
② After unpacking, the surface of the welding wire should be prevented from condensation or condensation, or be polluted by rust, grease and other hydrocarbons, and the surface of the welding wire should be kept clean and dry.
③ When the welding wire is not used up and needs to be put in the wire feeding machine overnight, cover the wire feeding machine (or the welding wire plate) with canvas, plastic cloth or other articles to reduce the contact with moisture in the air.
④ for welding wires that are not used for more than 3 days, they should be removed from the wire feeding machine. Put it back into the original package, seal it, and then put it into the warehouse with good storage conditions.
3. Quality management of welding wire
① for the purchased welding wire, each batch of products should have the quality guarantee of the manufacturer. Each package of the products that have passed the inspection must contain the product specification and the product qualification certificate. The inner package of each piece of welding wire shall be marked with the welding wire model and corresponding national standard number, batch number, inspection number, specification, net quality, manufacturer name and factory address by using labels or other methods.
② pile up respectively according to the type and specification of welding wire to prevent misuse.
③ according to the principle of “First In First Out”, the welding wire is distributed to minimize the storage period of the welding wire.
④ if the welding wire packaging is found to be damaged, it should be carefully checked. For welding wires with obvious mechanical damage or excessive rust, they cannot be used for welding. It should be returned to the inspector or technical director for inspection and use approval.
4. Drying of welding wire
Drying is a common problem in the use of welding rod, but for the welding wire, in the actual construction, some people think that the welding wire with severe damp can also be dried, but the temperature should not be too high, generally, it can be dried at 130 ~ 160℃ for 1~2 hours. This is beneficial for eliminating pores and reducing diffused hydrogen content.