The product range of Hongchuang hardware fasteners includes hexagon head screws, full thread and half thread hexagon socket head cap screws, hexagon wood screws, hexagon socket head cap screws, full thread and half thread hexagon socket countersunk head screws, hexagon socket head flange screws, set screws, etc. We provide products conforming to DIN, ANSI and JIS standards.
Stainless steel of grade 304 contains nickel of 8% and chromium of 18% and is the most commonly used grade for the production of fasteners. It possesses an excellent combination of strength, corrosion resistance and fabricability. Fasteners of this grade are being extensively used today in almost every industry.
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So what exactly is the case with cold-rolled plates and under what circumstances are hot-rolled plates used? What is the difference between them? The following content or how much give us some understanding:
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Cold-rolling and hot-rolling are two different steel rolling technologies. As the name suggests, cold rolling is performed when the steel is spliced ​​at room temperature. The hardness of such steel is large. Hot rolling is the rolling of steel at high temperatures.
1. Continuous casting slabs or green rolled slabs for hot rolling are used as raw materials, heated in a step-type heating furnace, descaled after high-pressure water, and then into roughing mills. The rough rolling stock is passed through the cutting head, tail, and then into the finishing rolling mill to implement the computer. Controlled rolling, laminar cooling (computer controlled cooling rate) and coiler take-up, straight hair roll after finish rolling. The heads and tails of straight hair curls tend to be tongue-like and fish-tailed, with poor accuracy in thickness and width, and there are often defects such as wavy shapes, hemmed edges, and tower shapes at the edges. Its heavier roll weight and coil inner diameter is 760mm. (The general pipe industry likes to use it.) After straightening the hair straightening, cutting, trimming and multi-pass straightening, leveling and other finishing lines, then cutting or re-rolling, that is: hot rolling Steel plates, flat hot rolled steel coils, slitters and other products. Hot rolled finishing rolls, after pickling to remove oxide scales and oiling them, are ready for hot-rolled pickled coils. The product has the tendency to locally replace cold-rolled plates, and is affordable and popular with customers.
Hot rolling uses slabs (mainly continuous slabs) as raw materials. After heating, strips are made from rough rolling mills and finishing mills. The hot strip from the last rolling stand of the finish rolling is cooled by laminar flow to the set temperature. It is coiled by a coiler into a steel coil and the coiled steel coil is subjected to different finishing operations according to the user's different requirements. Lines (leveling, straightening, cross-cutting, slitting, inspection, weighing, packaging, marking, etc.) are processed into steel sheets, flat rolls, and slit strips. To put it simply, a piece of slab is heated after it has been heated (that is, the hot, red hot steel piece on TV), rolled, and trimmed to form a steel plate. This is called hot rolling.
Picture cold rolling: Using hot-rolled steel coils as raw materials, after pickling the scales and removing the oxide scales, cold rolling is performed. The finished products are rolled hard coils. The cold work hardening caused by continuous cold deformation increases the strength and hardness of the rolled hard coils. Toughness index decreases, so the stamping performance will deteriorate and can only be used for simple deformed parts. Rolled hard coils can be used as raw materials for hot dip galvanizing plants because the hot dip galvanizing lines are all provided with annealing lines. The weight of the rolled hard coil is generally 6~13.5 tons. The steel coil is continuously rolled at the normal temperature. The inner diameter is 610mm.
2. Hot rolled steel coils for cold rolling are used as raw materials, followed by tandem cold rolling after pickling to remove scales. The finished products are rolled hard rolls. The cold work hardening caused by continuous cold deformation increases the strength and hardness of the rolled hard rolls. Toughness index decreases, so the stamping performance will deteriorate and can only be used for simple deformed parts. Rolled hard coils can be used as raw materials for hot dip galvanizing plants because the hot dip galvanizing lines are all provided with annealing lines. The weight of rolled hard rolls is generally 6~13.5 tons, and the internal diameter of steel coils is 610mm.
General tandem cold-rolled steel plates and coils shall be annealed (CAPL unit) or bell furnace annealing to eliminate cold work hardening and rolling stress, and achieve the mechanical performance indicators specified in the corresponding standards. The surface quality, appearance and dimensional accuracy of cold-rolled steel are all superior to those of hot-rolled steel, and its product thickness can be rolled to about 0.18mm, so it is favored by customers. The deep processing of products using cold-rolled coils as a base plate has become a high value-added product. Such as electro-galvanized, hot-dip galvanized, anti-fingerprint electro-galvanized, color-coated steel coil and shock-absorbing composite steel plate, pvc laminated steel plate.
By definition, ingots or billets are difficult to deform at normal temperatures and difficult to process. Generally, they are heated to 1100 to 1250°C for rolling. This rolling process is called hot rolling. Most steels are rolled by hot rolling. However, because the surface of the steel is easily formed at the high temperature, the surface of the steel is rough, and the surface of the hot-rolled steel is rough and the size fluctuates greatly. Therefore, steels with smooth surfaces, precise dimensions, and good mechanical properties are required, and hot-rolled semi-finished products or finished products are used as raw materials and then cooled. Rolling method production.
Rolling at room temperature is generally understood as cold rolling. From the viewpoint of metallurgy, the boundaries between cold rolling and hot rolling should be distinguished by the recrystallization temperature. That is, the rolling below the recrystallization temperature is cold rolling, and the rolling above the recrystallization temperature is the hot rolling. The recrystallization temperature of steel is 450-600°C.
Simply say:
1. The surface of a cold-rolled plate has a certain degree of gloss and feels relatively smooth, similar to the very common steel cup used to drink water.
2. If the hot-rolled plate is not pickled, it is similar to the surface of many ordinary steel plates on the market. The rust-produced surface is red, and the rust-free surface is purple black (iron oxide scale). 5
the difference:
The performance advantages of cold-rolled and hot-rolled sheets are:
1. The precision is higher, and the difference between the thickness of cold rolled strip is not more than 0.01~0.03mm. The slide rails produced with cold rolled plates are balanced by force, so the slide rails produced by the same batch of materials are the same.
2, the size is thinner, the cold rolled thinnest rolled 0.001mm steel strip; hot rolling is now the thinnest can reach 0.78mm.
3, the surface quality is superior, cold-rolled steel plate can even produce a mirror surface; while the surface of hot-rolled plate has a defect such as iron oxide skin, pitting.
4. The cold-rolled sheet can be adjusted according to user requirements for its mechanical properties such as tensile strength and process properties such as stamping properties.
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Product features: Because it has not been annealed, its hardness is very high (HRB is greater than 90), and its machining performance is extremely poor. It can only perform simple directional bending processing (with a direction perpendicular to the take-up direction) of less than 90 degrees.
To put it simply, cold rolling is performed on the basis of hot-rolled coils. Generally speaking, it is hot-rolling, pickling, and cold-rolling.
Cold rolling is performed at normal temperature by hot-rolled sheet. Although the steel sheet is heated during rolling because of rolling, cold rolling is still called. Due to cold rolling after continuous hot rolling, the mechanical properties are poor and the hardness is too high. It must be annealed to restore its mechanical properties. No annealing is called rolled hard rolls. Rolled hard rolls are generally used to make products that do not need to be bent or stretched, and a thickness of 1.0 or less is used to roll hard sided or four-sided bends.
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1. Cold rolling is processed at normal temperature by hot-rolled sheet
2. After a slab has been heated (that is, the hot, red hot steel in the TV), it is rolled in several passes and trimmed to form a steel plate. This is called hot rolling.
Slide material: difference between cold rolled plate and hot rolled plate
The material of steel ball slides is generally produced by cold-rolled steel plates. Because the drawing requirements are relatively high, ordinary powder-drilling drawer slides are not difficult to find. They are hot-rolled plates because they require general tension.