Q235 steel plate welding technical requirements

In our country, welding operations need to be licensed, welders are the type of work that belongs to the access category, in the professional qualifications of skilled personnel, only five of the 81 types of work in the access category, welders are one of them, and the actual situation is that most of the industry practitioners are unlicensed operations. With the continuous standardization of technology and the relevant requirements of the industry, more and more people want to take a welding certificate, the advantage of the certificate is still very large, first of all, the salary of the certificate and the non-certificate are very different, often able to reach more than double or higher level. Therefore, the issue of short-term welder training has naturally become a concern for practitioners.

Welding as an industrial "tailor" is a very important means of processing in industrial production, the quality of welding plays a decisive role in the quality of the product, so, what is the future development of welding technology?

Industry outlook. With the development of production, welding is widely used in aerospace, aviation, nuclear industry, shipbuilding, construction and machinery manufacturing and other industrial sectors, in China's economic development, welding technology is an indispensable means of processing. After entering the 21st century, welding is an important part of the manufacturing industry, and the rapid development, so it has brought unprecedented development opportunities to the welding industry.

At present, China consumes 300 million tons of steel every year (about tons of welded structure), and needs about 750,000 welding machines, and the welding industry will continue to grow in the next 8 10 years.

Q235 steel plate belongs to low-carbon steel, because of the low carbon content of low-carbon steel, manganese and silicon content is also low, so under normal circumstances, it will not produce serious hardened or quenched structure due to welding. The plasticity and impact toughness of the joint after low carbon steel welding are good, and when welding, there is generally no need to preheat, control the interlayer temperature and post-heat, and there is no need to use heat treatment to improve the structure after welding, and the whole welding process does not need to take special technological measures, and the weldability is excellent.

But in a few cases, difficulties can also arise when welding:

J507 electrode for Q235 channel steel and Q355 iron plate welding, see GB 50236-2011 table for details.

Hello, Q235 channel steel and Q355 iron plate welding with E4303 (J422) electrode welding. (The principle of electrode selection is: low is not high).

Summary. The external implementation standard of Q235 is: GB T709-2006, and the internal implementation standard is: GB T3274-2007.

The external implementation standard of Q235 is: GB T709-2006, and the internal implementation standard is: GB T3274-2007.

The mandatory standard is preceded by "GB". It is recommended that the standard for splintering manuscripts be named "GB T". Compared with many ISO international standards, many national standards are equivalent to the adoption of (IDT, identical to other standards), and the use of repair and potato Zheng reform (mod, modified in relation to other standards.

Prior to 2000, it was called "Equivalent Acceptance, EQV, Equivalent to Other Standards" or "NEQ, Not Equivalent to Other Sakurai Standards".

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Three thick steel plates, what is the allowable error.

3 The steel plate is allowed to have errors, and its error range is on the left and right, which is the standard error.

Yes, it can be welded. Because the process of welding is the process of melting or re-smelting, stainless steel and ordinary steel are both steel, so they can be welded.

Stainless steel and ordinary steel welding belong to dissimilar steel welding, according to different base metals to choose different welding consumables, but the welding consumables used must be austenitic stainless steel electrode welding wire, if argon arc is used, argon protection should be carried out.

When welding with stainless steel electrodes, use as little current as possible, reduce the wobble when transporting the bar, hammer the weld bead, relieve the stress, and keep the temperature of the workpiece as low as possible. In this way, welding does not need to be preheated, can be welded directly, and small diameter welding rods should be used as much as possible.

If it is already quenched and tempered 45 steel, the welding is welded with dissimilar rigid electrodes.

In general, manual arc welding is used, and alkaline structural steel electrodes such as J507, J506, and J427 are used. If there are no special requirements, general J422 welding rods can also be used.

No. 45 steel is a high-quality carbon structure steel, the hardness is not high and easy to cut, and it is commonly used in the mold to make templates, pins, guide pillars, etc., but it must be heat treated.

On the basis of the principle of ordinary arc welding, argon arc welding technology uses argon to protect metal welding consumables, and melts the welding consumables into a liquid state on the welded substrate to form a molten pool through high current, so that the welded metal and the welding consumables achieve metallurgical combination.

No. 45 steel and Q235 are welded with ordinary J506 electrodes, and DC welding machines are reversed welded.

Use titanium-calcium low-carbon structural steel electrode J422 (E4303 electrode can be welded).

It is an acid electrode, coating titanium-calcium type, J means structural steel electrode, 42 is the tensile strength of 42kg mm2 weld metal.

It is used for welding low-carbon steel structures and low-alloy steels with low strength grades, and is generally used for welding steel structures and ordinary carbon steel pipes.

It is mainly used for welding low-carbon steel structures and low-alloy steels with low strength grades, and is generally used for welding steel structures and ordinary carbon steel pipes.

Summary. The common welding processes of Q355B I-beam enterprises include manual arc welding of welding wire, automatic welding machine for submerged arc welding and carbon dioxide gas maintenance welding, and sometimes molten nozzle electroslag welding is also used in some places.

Q355B Gongshen Lizi Steel Enterprise Electric Return Welding I-beam Common welding processes include welding wire manual arc welding, submerged arc welding automatic welding machine and carbon dioxide gas maintenance welding, and sometimes molten nozzle electroslag welding is also used in some places. Kuanshi search.

Workers in the construction industry often have to weld the reed wax I-beam, such as: the tunnel with the sliding construction of the early stage of the bolt support I-beam cast-in-place beam in the production and processing, some of the length of the I-beam after the material is less than the length of a module, the workers will carry out the I-beam welding welding, silver large welding welding first use electricity electrode arc welding connection, and then weld a thick steel plate on both sides of the beam end, the thickness of the steel plate is different.

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What wire or electrode is used to weld No. 45 steel with Q235 and what welding equipment is needed?

Hello, Q235 belongs to the low carbon structural steel grade; No. 45 steel is a high-quality medium carbon steel grade, and the welding of the two belongs to dissimilar metal welding. It can be welded with J50 series electrodes of one grade lower than 45 steel and one grade higher than Q235 steel. Such as:

Grade J506, model E5016, low hydrogen potassium type low alloy structural steel electrode; Grade J507, model E5015, low hydrogen sodium type low alloy structural steel electrode welding.

The steel of Q355 and the steel of Q235 can be welded directly, because according to GB 50236, they are of the same category and group, and even dissimilar steels can be welded together. Use the common J422 (AC and DC dual-use) or J427 electrode (DC reverse connection). These two electrodes have the same strength level, which can meet the requirements of Q235, although the strength of Q355 is a little higher, but when welding with Q235, you can choose according to the lower side.