Q355c is a kind of steel. It is a low-alloy high-strength structural steel, widely used in bridges, vehicles, ships, construction, pressure vessels, special equipment, etc., where “Q” indicates the yield strength, 355 means the yield strength of this steel is 355MPa, which will change with the increase of material thickness, and its yield value will be reduced.
Chemical composition: C: ≤ 0.24, Si: ≤ 0.55, Mn: ≤ 1.60, P: ≤ 0.035, S: ≤ 0.035, Cr: ≤ 0.30, Ni: ≤ 0.30, Cu: ≤ 0.40.
Yield strength: ≤ 16mm: ≥ 355, 16-40: ≥ 345, 40-63: ≥ 335, 63-80: ≥ 315, 100-150: ≥ 295, 150-200: ≥ 285, 200 – 250: 275
Tensile strength: 450-630.
Impact test: temperature: 0 ℃: longitudinal ≥ 34, transverse ≥ 27.
Elongation: ≥ 21.
Q355c angle steel is a channel-shaped steel profile. The whole steel is a long strip. The q355c angle steel is mainly used in machinery and construction, especially machinery. There are also many reasons why q355c angle steel is used in machinery, most of them are used in the chassis of large equipment. Q355c angle steel has a high load-bearing capacity and is a necessary material for installing heavy machinery. With the significant increase in demand for q355c angle steel in the industrial sector, the demand for q355c angle steel from companies has also started to increase.
There are many requirements for the appearance of q355c angle steel. If there are deviations in the surface quality of q355c angle steel, the deviations must be within the relevant regulations and must not exceed this standard. Such standards are set by the relevant national authorities and are not official standards. In addition to the surface quality of q355c angles that need to be produced within the allowable deviation, the dimensional deviation of q355c angles must also meet the requirements of the standard.
Q355c angle is also specified in appearance. If there is a defect on the surface of the q355c angle, this defect will never cause damage when using the q355c angle. If there is damage, the q355c angle cannot be used directly. The q355c angle itself should be horizontal, if the twist is large, this q355c angle cannot be used further. Waves may appear on the q355c angle, which is unavoidable. However, the waveform curve must be within the specified standard range.
When specifying the standard of q355c angle, there are also strict regulations for each parameter of the surface of q355c angle, and these regulations include its explicit and differential values. If the geometry of the q355c angle is incorrect, in fact, people can fully see some different points of the q355c angle, such as the expansion of the q355c angle and the leaning of the q355c angle leg. These are the things that companies pay special attention to in appearance control.
Work piece → degreasing → water washing → pickling → water washing → dipping co-solvent → drying preheating → finishing → cooling → passivation → water washing → drying → inspection
(1) Degreasing
Chemical degreasing or water-based metal degreasing cleaning agent can be used to decrease until the workpiece is completely wetted by water.
(2) Pickling
Available H2SO415%, thiourea 0.1%, 40～60℃ or HCl20%, urotropine 3～5g/L, 20～40℃ pickling. The addition of corrosion inhibitors can prevent the substrate from over corrosion and reduce the amount of hydrogen absorption of the iron substrate. Meanwhile, the addition of an atomization inhibitor can inhibit the escape of acid mist. Improper treatment of degreasing pickling can result in poor adhesion of the plating layer, no galvanized layer, or flaking of the zinc layer.
(3) Immersion flux
Also known as a solvent, it can keep the workpiece active before immersion plating to avoid secondary oxidation, thus enhancing the bonding of the plating layer with the substrate. NH4Cl100-150g/L, ZnCl2150-180g/L, 70-80℃, 1~2min. and add a certain amount of anti-explosive agents.
(4) Drying and preheating
To prevent deformation of the workpiece due to a sharp rise in temperature during dipping and plating, and to remove residual moisture and prevent zinc explosion caused by zinc explosion, preheating is generally 80-140℃.
There are many types of q355c angle steel components and more manufacturing processes. The first one is the most commonly used solvent method. Due to the wide variety of our steel components, there are many methods used, but we basically do not use it in the design of spreader. In general, the spreader designer needs to consider some factors. What are these factors? First of all, it must be easy to operate and add as little galvanizing liquid to it as possible. Here is that the hanging must be very strong, and our steel members require a certain strength and do not agree to be damaged, which emphasizes the main reason why it is not easily deformed. Our steel members have many requirements, not only used in our q355c angle, more importantly, there are many other uses, and with the different types of use, we put forward different requirements, which is also the main our social development needs.
The formation process of the q355c angle layer is the formation of an iron-zinc alloy between the iron substrate and the outermost pure zinc layer. The surface of the workpiece forms an iron-zinc alloy layer during hot-dip plating, giving an excellent connection between the iron and the pure zinc layer. The process can be briefly described as follows: When the iron workpiece is immersed in the molten zinc solution, a solid solution of zinc and alpha iron (body nuclei) is first formed at the interface. This is a crystal consisting of base metal iron dissolved in solid zinc atoms. The two metal atoms are fused together and the interatomic gravitational force is relatively low.
Therefore, when zinc reaches saturation in the solid solution, the atoms of both elements, zinc, and iron, disperse from each other and the zinc atoms dispersed (or called into) the iron matrix move in the matrix lattice, gradually forming an alloy with iron and dispersing the iron and zinc in the molten zinc to form the intermetallic compound FeZn13, which sinks to the bottom of the hot-dip galvanizing pot and is called zinc dross. When the workpiece is removed from the zinc dip, the surface forms a pure zinc layer, which is a hexagonal crystal system. Its iron content does not exceed 0.003%.
The corrosion resistance of hot-dip galvanizing is much higher than that of cold-dip galvanizing (also known as electro-galvanizing). Hot-dip galvanizing does not rust for several years, while cold-dip galvanizing rusts in six months.
The cold galvanizing process is used to protect metals from corrosion. For this purpose, a zinc filler coating is used, which is applied to the protected surface by any coating method. After drying, a zinc filler coating is formed. Zinc (up to 95%) is contained in the dry coating. Steel pipes are surface galvanized under cooling conditions, while hot-dip galvanizing is the surface of steel pipes under hot dipping conditions. The adhesion is strong and does not come off easily. Although hot-dip galvanized pipes also rust, they can meet technical and sanitary requirements for a long time.
When users buy q355c angles, it is very important to choose a genuine product. We all know that for this product when it is produced, it is allowed to exist in the product because of different manufacturers or different brands. Authenticity is also different, when the authenticity is different, it will naturally show a different service life, different service life, different performance, etc. Therefore, when users buy the product, its authenticity is the most important, so how can users buy the product to meet the requirements of authenticity?
First, let q355c angle steel reach a good brand. As we all know, for the manufacturers now, there are many, some are small products, some are brands, if the product to achieve authenticity, the first choice is a big brand, some users like to let themselves buy some cheap products when buying. For these products, although the price is very low, their products can not achieve the above performance. Can not reach the long service life.
Therefore, users should not be greedy for its cheap price when buying q355c angle steel. On the other hand, is for users to choose the important place to buy. For some brands, there are also some fake products. Exist, so users can not let themselves show a good sales law when buying, it is easy to buy counterfeit products, so this aspect is also important. Finally, the user must pay attention to the production of the product when buying. Note that only the regular production number ensures the authenticity of the product.
Hot-dip galvanized also has color hot-dip galvanized angles, printed coated galvanized angles, PVC laminated hot-dip galvanized angles, etc., but the most commonly used is still hot-dip galvanized steel pipe. Galvanized steel sheets can be classified into general-purpose, roofing purpose, building facade panel purpose, structural purpose, corrugated panel purpose, deep-drawing purpose, and deep-drawing purpose. The relevant product standards for dimensional specifications list the recommended standard thickness, length, width, and allowable deviation of galvanized steel sheets. The surface condition of hot-dip galvanized angles varies due to the treatment method in the plating process, such as plain zinc bloom, fine zinc bloom, flat zinc bloom, zinc bloom without zinc, phosphate treated surface, etc. The German standard also specifies the surface grade. The galvanized sheet should have a good appearance and should not have defects that are harmful to the use of the product such as no plating, holes, cracks, scum, the excessive thickness of plating, scratches, chromic acid stains, white rust, etc. . Foreign standards are not very clear about the specific appearance defects. Some specific defects should be listed in the contract when ordering. The standard value of galvanized layer: Galvanized layer is a commonly used and effective method to indicate the thickness of the zinc layer of galvanized sheet.
Angle steel production process is long, many processes, strip steel dipped into the zinc pot and zinc pot after the formation of the coating, cooling solidification process is very complex. Therefore, there are many factors affecting the angle steel, and the influence of each influencing factor on the performance of the angle steel coating is not isolated, but intertwined and interacting with each other. The factors that determine the quality of the angle steel are mainly in the following four areas.
1, cooling passivation: steel parts are cooled in the water tank after the angle. The cooling water is usually tap water. Steel parts should be cooled as soon as possible after being lifted from the zinc pot to avoid deformation of the workpiece. The optimum temperature should be between 30°C and 70°C. An appropriate amount of surfactant can be added to the water to improve the surface gloss of the steel parts.
2. Use of tooling: The tooling of angles is very important in the galvanizing process. Good tooling can greatly improve the yield and quality, but the design of the tooling depends on the type of galvanized parts, so it needs to be designed and produced on-site. The design of the tooling should take into account the production capacity, shape, and size of the steel parts as well as the technical requirements of the customer.
3、Operating speed: When dipping steel parts, it should be as fast as possible while ensuring the safety of workpiece and personnel to ensure consistent film thickness in all parts of galvanized parts. Lifting speed should be determined by the steel structure, material, and length. Use different speeds. A general lifting speed of 1.5m/min can ensure better zinc reflux and surface brightness.
4、Refurbishment inspection: Check the thickness and appearance of the paint film of the plated parts according to the requirements and standards (GB/T13912-2002), and polish the zinc powder and zinc slag attached to the surface of the plated parts to meet the requirements. Send for inspection and leave the factory.
