Q355C angle steel chemical composition and mechanical properties

Q355c is a kind of steel. It is a low-alloy high-strength structural steel, widely used in bridges, vehicles, ships, buildings, pressure vessels, special equipment, etc., where “Q” means yield strength, and 355 means that the yield strength of this steel is 355MPa, and will vary with As the thickness of the material increases, its yield value decreases.

1. chemical composition

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.

2.Mechanical properties

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 related process description

Q355c angle steel is a steel profile with a groove shape. The entire steel is a long strip. The main application of q355c angle steel is in machinery and construction, especially in machinery. There are also many reasons why q355c angle steel is used in machinery, most of which are used on the chassis of large equipment. Q355c angle steel has a high load-bearing capacity and is a necessary material for the installation of heavy machinery. With the great increase in the demand for q355c angle steel in the industrial field, enterprises’ requirements for q355c angle steel have also begun to increase.

There are many appearance requirements for q355c angle steel. For example, if there is a deviation in the surface quality of q355c angle steel, the deviation must be within the relevant regulations and cannot exceed this standard. Such standards are formulated by relevant national departments, rather than unofficial standards. In addition to the surface quality of q355c angle steel that needs to be produced within the allowable deviation range, the dimensional deviation of q355c angle steel must also meet the requirements of the standard.

Q355c angle steel also has regulations on appearance. If there is a defect on the surface of q355c angle steel, this defect will definitely not cause damage when q355c angle steel is used. If there is damage, q355c angle steel cannot be used directly. The q355c angle steel itself should be horizontal, if the torsion amplitude is large, this kind of q355c angle steel cannot continue to be used. Waves may appear on the q355c angle steel, which is inevitable. But the wave curve must be within the specified standard range.

When specifying the standard of q355c angle steel, there are also strict regulations on the various parameters of the q355c angle steel surface, and these regulations include its detailed value and the difference value. If the geometric shape of the q355c angle steel is incorrect, in fact, everyone can fully see some of the different points of the q355c angle steel, such as the expansion of the q355c angle steel angle and the close together of the q355c angle steel legs. These are the things that enterprises pay special attention to in appearance control.

crafting process

Workpiece → Degreasing → Water Washing → Pickling → Water Washing → Dipping Support Solvent → Drying and Preheating → Finishing → Cooling → Passivation → Rinsing → Drying → Inspection

q355c angle steel related process description

(1) Degreasing

Chemical degreasing or water-based metal degreasing cleaning agent can be used to degreasing until the workpiece is completely wetted by water.

(2) Pickling

It can be pickled with H2SO415%, thiourea 0.1%, 40～60℃ or HCl20%, urotropine 3～5g/L, 20～40℃. The addition of corrosion inhibitors can prevent the matrix from over-corrosion and reduce the hydrogen absorption of the iron matrix. At the same time, the addition of a fog inhibitor can inhibit the escape of acid mist. Poor degreasing and pickling treatments will cause poor adhesion of the coating, no zinc coating, or peeling 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, so as to enhance the bonding between the plating layer and 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

In order to prevent the workpiece from deforming due to the sharp rise in temperature during immersion plating, and to remove residual moisture, to prevent zinc explosion and cause zinc liquid explosion, the preheating is generally 80-140°C.

The technical difference of q355c angle steel

There are many types of q355c angle steel components, and there are relatively many manufacturing processes. The first is the most commonly used solvent method. As our steel structural parts are diverse, there are many ways to use them, but basically we don’t use them in the design of the spreader. Under normal circumstances, the spreader designer needs to consider some factors. These What are the factors? First of all, it must be easy to operate, try to add some galvanizing liquid in it as little as possible, here is that the hanging must be very strong, and our steel components are required to have a certain strength, do not agree to damage, this It emphasizes the main reason why it is not easy to deform. There are many requirements for our steel components, not only used in our q355c angle steel, more importantly, there are many other uses, and with the different types of use, the requirements we put forward are also different, this is also With the main requirements of the development of our society.

The angle steel production process is long and there are many procedures, and the formation of the coating after the strip is immersed in the zinc pot and the zinc pot, and the cooling and solidification process is very complicated. Therefore, there are many factors that affect the angle steel, and the influence of each influencing factor on the performance of the angle steel coating is not Isolated but intertwined and interacted. The factors that determine the quality of angle steel are mainly manifested in the following four aspects:

1.Cooling passivation: The steel parts are cooled in the water tank after the angle steel. The cooling water generally taps water. The steel parts should be cooled as soon as possible after being hoisted from the zinc pot to keep the workpiece from deforming. The best 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 steel parts.

2.The use of tooling: the tooling of angle steel is very important to the galvanizing process. Good tooling can greatly increase the output and quality, but the design of the tooling depends on the type of galvanized parts, so it needs on-site design and production. The design of the tooling should take into account the production capacity, the shape and size of the steel parts, and the technical requirements of the customer.

3.Operating speed: When steel parts are immersed, they should be as fast as possible under the premise of ensuring the safety of workpieces and personnel, so as to ensure that the film thickness of all parts of the galvanized parts is the same. The lifting speed should be based on the steel structure, material, and length. Different speeds are used. Generally, a lifting speed of 1.5 m/min can ensure better zinc liquid reflux and surface brightness.

4.Refurbishment inspection: inspect the film thickness and appearance of the plated parts in accordance with the requirements and standards (national standard GB/T13912-2002), and polish the zinc dust and zinc slag attached to the surface of the plated parts to meet the requirements. Submit for inspection and leave the factory.