Nondestructive testing technology in the whole production process of stainless steel cap

 1、 Radiographic examination

　　The radiographic inspection method is applicable to the inspection of internal defects of pressure vessel cap cover or butt weld. Generally, the thickness of steel suitable for inspection by X-ray flaw detector is not more than 80mm, the thickness range of lr-192 inspection is 20 ~ 100mm, and the thickness of Co-60 inspection is 40 ~ 200mm.

　　2、 Surface inspection

　　The magnetic particle or penetration method is generally used for the surface inspection of thick steel plate welds, fillet welds and butt welds during the production and manufacturing of pressure vessel cap, and also for the surface inspection of large and medium-sized steel castings after machining.

　　3、 Ultrasonic testing

　　The ultrasonic inspection method is applicable to the inspection of the internal defects of the butt weld of the pressure vessel cap shell with a thickness of more than 6mm.

Preparation for carbon steel flange measurement

 With the rapid development of domestic and foreign pipeline construction, the carbon steel flange blind plate has become an indispensable and important part of the pipeline pressure test. Before and after the pressure test, each section of the pipeline must be cleaned by passing the ball, usually 4-5 times. Especially after the pressure test, it is difficult to clean the water stored in the pipeline, and the cleaning times will be more. The construction method of repeatedly welding the head at the ball receiving place has the following problems: first, increasing the labor intensity of workers; Second, the repeated welding head method has high consumables, requires many times of large-scale equipment and high cost. In view of the problems of high labor intensity, high consumables, many times of large-scale equipment and high cost caused by the repeated welding head method at the launching point when the ball cleaning is carried out after the pressure test of long-distance pipeline, a new simple quick opening large-scale flange blind plate construction method is proposed. Before the measurement of carbon steel flange, certain preparations shall be made, and the measurement shall be carried out according to certain ways and methods. Different measurement methods shall be determined according to specific conditions to ensure the accuracy of measurement.

　　Preparation before measurement:

　　1. before measurement, according to the position of the large flange, the sketch of each connecting large flange of the equipment shall be drawn and numbered continuously, so that the fixture can be installed in a certain way and principle to ensure normal use.

　　2. during installation, the carbon steel flange may have different outer diameters, staggered joints and unequal gasket thickness, so the machined fixture should correspond to the carbon steel flange on the side and cannot be interchanged. Therefore, measuring the size and number of each part is the key to fixture processing and installation

　　3. when measuring, it is better to arrange three people, two of whom measure, one of whom proofreads and fills in the form, and the measuring tool is vernier caliper. If there is no condition, the external caliper and steel ruler can be used Measurement is a meticulous work and a prerequisite for fixture installation. Measurement and recording must be prepared without error and the form must be filled out carefully and clearly In the actual measurement work, we should cooperate with each other and be able to cooperate and use according to the correct principle.

Desulfurization process of carbon steel elbow

 　Desulfurization in oxygen converter is difficult and uneconomical. In recent years, the supply of high-quality metallurgical coke is insufficient, the sulfur content of coke is the highest, and the sulfur content of heavy oil injected to strengthen blast furnace smelting is also high. As a result, the quantity and cost of low sulfur molten iron meeting the steel-making requirements are becoming more and more problematic. The practice has proved that it is a good way to solve the above contradiction to take off the hot metal outside the furnace between the blast furnace and the converter.

　　It can improve the technical and economic indexes of iron making and carbon steel elbow at the same time. It is particularly important to simplify the operation of converter and realize automatic control. It is developing rapidly in many countries. The basic principle of desulfurization outside the furnace is the same as that of bowl removal inside the furnace. That is, use elements or compounds with greater affinity to sulfur than iron and sulfur to convert iron sulfide into more stable sulfide that is rarely or completely insoluble in molten iron; At the same time, good kinetic conditions are created to accelerate the diffusion of sulfur in molten iron to the reaction area and expand the reaction area between desulfurizer and molten iron. ASTM 440 is named high strength carbon steel elbow.

　　Including Mn Cu high strength low alloy steel profiles, plates and bars. It is mainly used for riveting or bolting bridges and buildings. Welding is generally not appropriate. However, the material can also be welded after certain measures are taken. Due to the minimum content of 0.2%cu, its atmospheric corrosion resistance is about twice that of carbon structural steel without Cu. The minimum yield strength of steel plate with thickness below 19mm shall be 345mpa.

Equal diameter hot pressing pipe tee forming process

 Equal diameter hot pressing pipe tee forming process the thickness of the equal diameter tee and the reducing tee is used to express the detailed reducing main type, while the American Standard reducing tee uses Sch to express the pressure of the reducing tee. Before the reproduction of American Standard reducing tee and pressing cold extrusion, we must implement the wall thickness of reducing tee before further cold extrusion of reducing tee. If we don't know the wall thickness of the reducing tee, what if we make the cold extrusion reducing tee to meet the customer's requirements. This is a huge difference in wall thickness between our most common national standard reducing tee and American Standard reducing tee.

Small diameter seamless steel pipe

 In general, seamless steel pipes used in daily life are of normal caliber, and small caliber seamless steel pipes are used in some special places. Today, I'd like to introduce the relevant knowledge of small-diameter seamless steel pipe, which will help you better use this kind of pipe in the future. Generally speaking, seamless steel pipes with small outer diameter are collectively referred to as small-diameter seamless steel pipes, but there is still a specific range. Generally, those with steel diameter less than 89mm and more than 4mm can be called small-diameter seamless steel pipes.

　　In most cases, small-diameter seamless steel pipe is also used as a pipe for conveying fluid. Compared with solid steel such as round steel, it is light in weight when its bending and torsional strength is the same. It is a kind of economic section steel, which is widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipes, automobile transmission shafts, bicycle frames, steel scaffolds used in construction, etc.

　　The general specification of small-diameter seamless steel pipe is that its outer diameter is between 6-89mm, and its diameter is relatively small. The wall thickness of 1-12mm can also be divided into small-diameter thick wall seamless pipe and small-diameter thin-wall seamless pipe. Its weight calculation formula: [(outer diameter - wall thickness) * wall thickness] *0.02466 = kg/ meter (weight per meter)

　　In order to produce seamless pipes with smaller size and better quality, cold rolling, cold drawing or a combination of the two methods must be used. Cold rolling is usually carried out on a two high mill. Steel pipes are rolled in an annular pass consisting of a variable cross-section circular groove and a fixed conical plug. Cold drawing is usually carried out on a single chain or double chain cold drawing machine, that is, the hot tube blank is placed in a closed extrusion cylinder, and the perforated rod moves together with the extrusion rod to extrude the extruded part from the smaller die hole, so that small-diameter seamless steel pipe can be produced.

Desulfurization process of carbon steel elbow

 Desulfurization in oxygen converter is difficult and uneconomical. In recent years, the supply of high-quality metallurgical coke is insufficient, the sulfur content of coke is the highest, and the sulfur content of heavy oil injected to strengthen blast furnace smelting is also high, which makes the quantity and cost of low-sulfur molten iron meeting the requirements of steelmaking increasingly problematic. The practice has proved that it is a good way to solve the above contradiction to take off the bowl of molten iron outside the furnace between the blast furnace and the converter.

　　It can improve the technical and economic indicators of ironmaking and carbon steel elbow at the same time. It is particularly important for the converter to simplify operation and realize automatic control. It is developing rapidly in many countries. The basic principle of desulfurization outside the furnace is the same as that of desulphurization inside the furnace. That is to use elements or compounds with greater affinity to sulfur than iron and sulfur to transform iron sulfide into more stable, rarely soluble or completely insoluble sulfide in molten iron; At the same time, create good kinetic conditions to accelerate the diffusion of sulfur in molten iron to the reaction area and expand the reaction area between desulfurizer and molten iron. ASTM 440 is called high-strength carbon steel elbow.

　　It includes Mn-Cu high-strength low-alloy steel profiles, plates and bars. It is mainly used for riveting or bolting bridges and buildings. Generally, welding is not suitable. However, the material can also be welded after taking certain measures. Since it contains a minimum of 0.2% Cu, its atmospheric corrosion resistance is about twice that of carbon structural steel without Cu. The minimum yield strength of steel plate with thickness less than 19mm is 345MPa.

ASTM A500/ A501 ERW Steel Pipe

 ASTM A500/ A501 ERW Steel Pipe

ASTM A500/ A501 is a standard specification for cold-formed welded and seamless carbon steel structural tubing in round, square and rectangular shapes.