| The main production of customized hexagonal steel pipe, special-shaped steel pipe, oval pipe, special-shaped pipe, low-cost, honest and reliable, trustworthy. The special-shaped pipe is generally divided into seamless steel pipe, special-shaped pipe, aluminum alloy special-shaped pipe and plastic special-shaped pipe according to the material. The following mainly introduces the special-shaped steel pipe.
The special-shaped seamless steel pipe is the general term of seamless steel pipe with other cross-section shapes except round pipe.
According to the shape and size of steel pipe section, it can be divided into three types: equal wall thickness special-shaped seamless steel pipe (Code: D), unequal wall thickness special-shaped seamless steel pipe (Code: BD), variable diameter special-shaped seamless steel pipe (Code: BJ).
Special shaped seamless steel pipe is widely used in various structural parts, tools and mechanical parts. Compared with the circular pipe, the special-shaped pipe has larger moment of inertia and section modulus, and has greater bending and torsion resistance, which can greatly reduce the structural weight and save steel.
Special shaped steel pipe can be divided into oval shaped steel pipe, triangle shaped steel pipe, hexagonal shaped steel pipe, rhombic shaped steel pipe, octagonal shaped steel pipe, semicircular shaped steel circle, unequal hexagon shaped steel pipe, five petal plum shaped special-shaped steel pipe, double convex shaped steel pipe, double concave shaped steel pipe, melon seed shaped shaped steel pipe, conical shaped special-shaped steel pipe and corrugated shaped special-shaped steel pipe.
The specification of spiral steel pipe is 219mm-2020 mm, and the wall thickness is 5mm-20mm. The straight seam specification includes 4 points, 6 points, 1 inch, 1.2 inch, 1.5 inch, 2 inch, 2.5 inch, 3 inch, 4 inch, 5 inch, 6 inch, 8 inch, 102, 108, 127, 133, 139, 159, 168, 177, 194, 219, 273 325 and other special-shaped pipes generally refer to square rectangular steel pipes.
Performance index analysis editor
1. Performance index analysis of profiled steel pipe plasticity
Plasticity refers to the ability of metal materials to produce plastic deformation (permanent deformation) without damage under load.
2. Performance index analysis of profiled steel pipe hardness
Hardness is the indicator to measure the hardness and softness of metal materials. At present, the most commonly used method to determine the hardness in production is the indentation hardness method. It uses a certain geometric shape of the indenter to press into the surface of the tested metal material under a certain load, and then determines the hardness value according to the degree of indentation.
3. Performance index analysis of profiled steel pipe fatigue
The strength, plasticity and hardness discussed above are the mechanical properties of metals under static load. In fact, many machine parts work under the cyclic load, under which the parts will produce fatigue.
4. Performance index analysis of profiled steel pipe - impact toughness
The load acting on the machine parts with high speed is called impact load, and the ability of metal to resist damage under impact load is called impact toughness.
5. Performance index analysis of profiled steel pipe - strength
Strength refers to the ability of metal materials to resist failure (excessive plastic deformation or fracture) under static load. Because the action mode of load has the form of tension, compression, bending, shear, so the strength is also divided into tensile strength, compressive strength, bending strength, shear strength and so on. There is a certain relationship between various strengths, and tensile strength is usually used as the most basic strength indicator in use.
Sharp corner concept editor
【1】 The concept of special-shaped steel pipe, rectangular pipe, square pipe: the traditional welding stainless steel square rectangular pipe is usually produced with a turkey head roller and several square rectangular rollers. The production mainly relies on the flat roll rolling. Because the flat roll is a two roll structure, there are problems such as unequal roll gap and inconsistent stress state at the corner of square rectangular tube, resulting in the four corners of square rectangular tube not sharp, r = 1.2t, rectangular pipe ruler is the radius of external fillet, f is the wall thickness. Although it is in line with the relevant enterprise standards, it can not meet the user's requirements for high-quality products. The new design adopts Turkey head four roll rolling shaping. Because the four roll structure of Turkey head is the same, the roll gap of four corners is equal, and the stress state of corner is consistent. When the rolling force is large enough, the plastic deformation of the corner occurs, which makes the metal fill the corner. The intersection line between the plane and the arc surface is formed on the outer surface of the tube, namely sharp angle,
【2】 The deformation mechanism of rectangular tube is different from that of ordinary square rectangular tube by bending. It depends on the rolling force of roller, and produces extrusion force F through arc arch. As shown in Fig. 2, plastic deformation occurs at the corner of steel strip, so as to make special-shaped steel pipe and rectangular pipe, The square tube is formed by filling the corner. The first four rollers act on the same cross-section of the steel strip on a certain arc surface, which satisfies the conditions of formula (1), that is, the corner metal can be plastic deformed and sharp angle can be formed by roller pressure.