carbon steel pipe fitting and flange: 一月 2023

2023年1月31日星期二

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.

2023年1月28日星期六

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.

EN 10217 ERW Steel Pipe

Carbon Seamless Steel Pipe

ASTM A312 Ss304 / 316l Cold Rolled Seamless Stainless Steel Pipe

ASTM A312 ss304/ss 316L hot rolled low price seamless stainless steel pipe
We are a professional MANUFACTURER of Steel pipe and Fittings since 1989, Providing exceptional quality and service with competitive pricing for S. S. Seamless pipes, S. S. Welded Pipes, C. S. Seamless Pipes, Alloy Steel Seamless Pipes, High Pressure Fittings, Butt weld Fittings, Flanges and Valves.

Hot Rolled ASTM A53 Sch40 Carbon Seamless Steel Pipe

ASTM A335 Alloy Steel Pipe

Standard: ASME SA 335 American society of mechanical engineers; ASTM A335M American society for Testing and Materials

Uses: For manufacture wall panel, economizer, reheater, superheater and steam pipeline of boilers.

ASTM A519 Alloy Steel Pipe

Name: ASTM A519 Alloy Steel Pipe

Application:For mechanical and high-pressure settings, as well as for transporting steam, water and gas.

Size (mm): O.D.: 4"-26"; W.T.: 0.315"-2.5"

ASTM A213 Alloy Steel Pipe

ASTM A213 Alloy Steel Pipe for seamless ferritic and austenitic alloy-steel boiler, superheater, and heat-exchanger tubes

Alloy Steel Pipe

ASTM A312 Stainless Steel Pipe

ASTM A312 covers seamless, straight-seam welded, and heavily cold worked welded austenitic stainless steel pipe intended for high-temperature and general corrosive service.

　　Optional supplementary requirements are provided for pipe where a greater degree of testing is desired. These supplementary requirements call for additional tests to be made and, when desired, it is permitted to specify in the order one or more of these supplementary requirements.

　　Nominal Pipe Size (NPS): 1/8, 1/4, 3/8, 1/2, 3/4, 1, 11/4, 11/2, 2, 21/2 inch

　　Outside Diameter: 10,3 - 73 mm (0,405 - 2,875 inch)

　　Wall Thickness: 1,73 - 7,01 (0,068 - 0,276 inch)

　　Notes:

　　Steel Grades - TP 304, TP 304L, TP 316, TP 321

　　Size of pipes in accordance with ANSI/ASME B36. 19M.

　　All technical requirements in accordance with ASTM A530.

　　Length tolerance of measured pipes is not greater than +10 mm.

　　The quality of pipes is ensured by manufacturing process and non-destructive test.

　　Intergranular corrosion test in accordance with ASTM A262, Practice E is available.

ASTM A778 Stainless Steel Pipe

ASTM A778 Standard Specification for Welded Unannealed Austenitic Stainless Steel Tubular Products covers straight seam and spiral butt seam welded unannealed austenitic stainless steel tubular products intended for low and moderate temperature and corrosive service where treatment is not necessary for corrosion resistance.

ASTM A268 Stainless Steel Pipe

　ASTM A268 Standard Specification for Seamless and Welded Ferritic and Martensitic Stainless Steel Tubing for General Service. Covers standard specification for a number of grades of nominal wal thickness, welded ferritic and martensitic stainless steel tubing for general corrosion-resisting and high-temperature service.

　　The steel shall conform to the required chemical composition for carbon, manganese, phosphorus, sulfur, silicon, nickel, chromium, molybdenum, aluminum, copper, nitrogen, titanium, and columbium. The number of tubes in a lot heat treated by the continuous process shall be determined from the size of the tubes. The steel shall conform to the following tensile properties: tensile strength, yield strength, and elongation.

　　The tubes shall have a hardness number that will not exceed the prescribed Brinell and Rockwell hardness values. Several mechanical tests shall be conducted, namely: tension test; flaring test (for seamless tubes); flange test (for welded tubes); hardness test;flattening test; intergranular corrosion test; and hydrostatic or nondestructive electric test.

　　Grade TP439 is used primarily for hot-water tank service and does not require post-weld heat treatment to prevent attack of the heat affected zone.

　　Note 1-TP329 (S32900) formerly in this specification. has been transferred to Specifications A 789/A 789M and 790/A 790M.

　　An optional supplementary requirement is provided,and when desire, shall be so stated in the order.

　　Note 2-For tubing smaller than 1/2 in. [12.7 mm] in outside diameter, the elongation values given for strip specimens in Table 2 shall apply. Mechanical properties requirements do not apply to tubing smaller than 1/8 in. [3.2mm] in outside diameter or with walls thinner than 0.015 in. [0.4 mm].

ASTM A632 Stainless Steel Pipe

ASTM A632 Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing (Small-Diameter) for General Service covers grades of stainless steel tubing for general corrosion-resisting and low or high-temperature service. The tubes shall be cold finished and shall be made by the seamless or welded process. All material shall be furnished in the heat-treatedcondition. The heat-treatment procedure shall consist of heating the material and quenching in water or rapidly cooling by other means. Tension tests, flaring tests, hydrostatic tests, air underwater pressure tests, and nondestructive electric tests shall be performed in accordance to the specified requirements.

　　1.1 This specification covers grades of stainless steel tubing in sizes under ½ down to 0.050 in. (12.7 to 1.27 mm) in outside diameter and wall thickness less than 0.065 in. down to 0.005 in. (1.65 to 0.13 mm) for general corrosion-resisting and low- or high-temperature service, as designated in Table 1.

　　Note 1—The grades of austenitic stainless steel tubing furnished in accordance with this specification have been found suitable for low-temperature service down to −325°F (−200°C) in which Charpy notched-bar impact values of 15 ft·lbf (20 J), minimum, are required and these grades need not be impact tested.

　　1.2 Optional supplementary requirements are provided and, when desired, shall be so stated in the order.

　　1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

ASTM A358 Stainless Steel Pipe

ASTM A358 Standard for Electric-Fusion-Welded Austenitic Chromium-Nickel Stainless Steel Pipe for High-Temperature Service and General Applications. Covers electric-fusion-welded austenitic chromium-nickel stainless steel pipe suitable for corrosive or high temperature service, or both, or for general applications.

　　The pipes shall be sorted into five different classes. Class 1 pipes shall be double welded by processes employing filler metal in all passes and shall be completely radiographed. Pipes of Class 2 shall be double welded by processes employing filler metal in all passes with no radiography. Both Class 3 and Class 4 pipes shall be single welded except that the weld pass of the latter exposed to the inside pipe surface may be without the addition of filler metal.

　　Pipes of Class 5 shall be double welded by processes employing filler metal and shall be spot radiographed. Weld defects shall be repaired by removal to sound metal and rewelding. Subsequent heat treatment shall be as required on the original welds. The finished pipes shall be subjected to transverse tension test, transverse guided-bend weld test, and hydrostatic test.

　　This specification covers electric-fusion-welded austenitic chromium-nickel stainless steel pipe suitable for corrosive or high-temperature service, or both, or for general applications. The dimensionless designator NPS (nominal pipe size) has been substituted in this standard for such traditional terms as “nominal diameter,”“size,” and “nominal size.”

　　This specification covers the grades of alloy and stainless steel listed in Table 1. The selection of the proper grade and requirements for heat treatment shall be at the discretion of the purchaser, dependent on the service conditions to be encountered.

　　Five classes of pipe are covered as follows:

　　Class 1—Pipe shall be double welded by processes employing filler metal in all passes and shall be completely radiographed.

　　Class 2—Pipe shall be double welded by processes employing filler metal in all passes. No radiography is required.

　　Class 3—Pipe shall be single welded by processes employing filler metal in all passes and shall be completely radiographed.

　　Class 4—Same as Class 3 except that the weld pass exposed to the inside pipe surface may be made without the addition of filler metal .

　　Class 5—Pipe shall be double welded by processes employing filler metal in all passes and shall be spot radiographed.

2023年1月12日星期四

Specification of angle steel

It is mainly divided into two categories: equal angle steel and unequal angle steel, among which unequal angle steel can be divided into unequal edge equal thickness and unequal edge unequal thickness.

　　The specification of angle steel is expressed by the dimension of side length and side thickness. At present, the specification of domestic angle steel is 2-20, and the number of centimeters of side length is taken as the number. The same angle steel often has 2-7 different edge thicknesses. The imported angle steel shall be marked with the actual size and thickness of both sides and relevant standards. Generally, large angle steel is more than 12.5cm long, medium angle steel is between 12.5cm and 5cm long, and small angle steel is less than 5cm long.

　　The order of inlet and outlet angle steel is generally based on the specifications required in use, and the steel grade is the corresponding carbon steel grade. Besides the specification number, angle steel has no specific composition and performance series. The delivery length of angle steel can be divided into fixed length and multiple length. The selection range of fixed length of domestic angle steel includes 3-9m, 4-12m, 4-19m and 6-19m according to different specifications. The length selection range of angle steel made in Japan is 6-15m.

　　The section height of unequal angle steel is calculated according to the length and width of unequal angle steel. It refers to steel with angular section and unequal length on both sides. It is a kind of angle steel. Its side length is 25mm × 16mm～200mm × l25mm。 It is rolled by hot rolling mill.

　　The general specification of unequal angle steel is: N50 * 32 -- N200 * 125, and the thickness is 4-18mm.

　　Unequal angle steel is widely used in various metal structures, bridges, machinery manufacturing and shipbuilding, various building structures and engineering structures, such as house beams, bridges, transmission towers, lifting and transportation machinery, ships, industrial furnaces, reaction towers, container racks and warehouses.

Q355 A36 42CrMo4 S235j2 S235jr S235j0 S275j2 S275jr S275j0 S355j2 S355jr S355j0 Cold Rolled Carbon Steel Plate

Product Description

Length	1000mm -12000mm
Thickness	0.2mm~300mm
Width	600mm-1250mm
Painted Surface	Electroplating, spraying, drawing, polishing
Main Standard	GB/T700 standard : Q235A,Q235B,Q235C,Q235D,Q235E
	EN10025 standard : S235JR,S235J0,S235J2
	DIN 17100 standard : St33,St37-2,Ust37-2,RSt37-2,St37-3
	DIN 17102 standard : StE255,WstE255,TstE255,EstE255
	ASTM standard : A36/A36M A36
	A283/A283M A283 Grade A,A283 Grade B
	A283 Grade C,A283 Grade D
	A573/A573M A573 Grade 58,
	Grade 65,Grade 70
Material	Carbon steel :Q195-Q420 Series,SS400-SS540 Series,S235JR-S355JR Series,ST Series,A36-A992 Series,Gr50 Series,etc.
Surface	Mild steel plain finish, hot dip galvanized, pre galvanized, color coated, ect.
Size Tolerance	±1%-3%
Processing method	Bending, Welding, Decoiling, Cutting, Punching, Polishing or as customer's request
Technology	Hot roll, cold roll, cold drawn, ect.
MOQ	1 Ton
Price Term	T/T,L/C,Western Union,Paypal,Apple Pay,Google Pay,D/A,D/P,MoneyGram
Certificate	ISO9001

Hot Rolled 25mm Thick Mild Ms Plate Q235 High Carbon Steel Sheet

Product Description

Product Name	Carbon Steel Plate
Length	1m-12m or as required
Width	0.6-2m or as required
Thickness	0.12-20mm, 0.8mm-300mm or as required
Standard	API 5L, ASTM A53-2007, ASTM A671-2006, ASTM A252-1998, ASTM A450-1996, ASME B36.10M- 2004, ASTM A523-1996, BS 1387, BS EN10296, BS 6323, BS 6363, BS EN10219, GB/T 3091-2001, GB/T 13793-1992, GB/T9711
Grade	10#-45#, 16Mn, A53-A369, Q195-Q345, ST35-ST52 Grade A, Grade B, Grade C
Technique	Hot roll, cold roll, cold drawn, ect.
Processing method	Bending, Welding, Decoiling, Cutting, Punching, Polishing or as customer's request
Thickness tolerance	±0.1mm
Material	Q345,Q345A,Q345B,Q345C,Q345D,Q345E,Q235B HC340LA,HC380LA,HC420LA B340LA,B410LA 15CRMO,12Cr1MoV,20CR,40CR,65MN A709GR50
MOQ	25 tons (We can provide free sample)
Shipment time	Within 15-20 workdays after receiving deposit or L/C
Export packing	Waterproof paper, and steel strip packed. Standard Export Seaworthy Package : 3 layers of packing. Inside is craft paper, Middle is water plastic film and outside GI steel sheet to be covered by steel strips with lock, with inner coil sleeve.
Supply Ability	2000 tons / month

Pipe cap parameters

　Pipe cap, also known as head, plug, cap, pipe cover and bulkhead, is a pipe fitting welded on the pipe end or installed on the external thread of the pipe end to cover and block the pipe. It is used to close the pipeline, and its function is the same as that of pipe plug.

Nominal Diameter		Outside Diameter at Bevel		Back to End
Nominal Diameter		Series A	Series B	E	T	E1
DN	NPS	Series A	Series B	E	T	E1
15	1/2	21.3	18	25	4.57	25
20	3/4	26.9	25	25	3.81	25
25	1	33.7	32	38	4.57	38
32	1.1/4	42.4	38	38	4.83	38
40	1.1/2	48.3	45	38	5.08	38
50	2	60.3	57	38	5.59	44
65	2.1/2	76.1(73)	76	38	7.11	51
80	3	88.9	89	51	7.62	64
90	3.1/2	101.6	-	64	8.13	76
100	4	114.3	108	64	8.64	76
125	5	139.7	133	76	9.65	89
150	6	168.3	159	89	10.92	102
200	8	219.1	219	102	12.70	127
250	10	273.0	273	127	12.70	152
300	12	323.9	325	152	12.70	178
350	14	355.6	377	165	12.70	191
400	16	406.4	426	178	12.70	203
450	18	457.2	478	203	12.70	229
500	20	508.0	529	229	12.70	254
550	22	559	-	254	12.70	254
600	24	610	630	267	12.70	305
650	26	660	-	267	-	-
700	28	711	720	267	-	-
750	30	762	-	267	-	-
800	32	813	820	267	-	-
850	34	864	-	267	-	-
900	36	914	920	267	-	-
950	38	965	-	305	-	-
1000	40	1016	1020	305	-	-
1050	42	1067	-	305	-	-
1100	44	1118	1120	343	-	-
1150	46	1168	-	343	-	-
1200	48	1220	1220	343	-	-
When T is less the dimension in parentheses, the height E is available. Otherwise E1 is available.

Manufacturing technology of carbon steel pipe fitting reducer

　　Reducer is a kind of pipe fitting used for pipe diameter. The commonly used forming process is reduced diameter pressing, expanded diameter pressing or reduced diameter plus expanded diameter pressing. Stamping can also be used for reducing pipes of some specifications.

　　a. Reducing / expanding forming

　　The reducing forming process of reducing pipe is to put the pipe blank with the same diameter as the large end of reducing pipe into the forming die, and press along the axial direction of the pipe blank to make the metal move along the die cavity and shrink. According to the size of reducing pipe, it can be divided into one-time pressing forming or multiple pressing forming.

　　b. Stamping forming

　　In addition to using steel pipe as raw material to produce pipe fitting reducer, some specifications of pipe fitting reducer can also be produced by steel plate stamping process. The shape of the die used for drawing refers to the size design of the inner surface of the pipe fitting reducer, and the blanking steel plate is stamped and stretched by the die.

　　Before the pipe fitting reducer is bonded, wipe the socket side and the outside of the socket with a dry cloth. When there is oil stain on the surface, wipe it with acetone. Pay attention to the following points:

　　1. Control caliber: DIN standard (dn10-dn150), 3A / IDF standard (1 / 2 "- 6"), ISO standard（ Ф 12.7- Ф 152.4)；

　　2. International Industrial Standards: DIN, ISO, SMS, 3a, IDF, etc;

　　3. Product material: stainless steel 304, 316, 316L;

　　4. Quality and application: the inside and outside of the pipe fitting reducer are treated with high-grade polishing equipment to meet the requirements of surface precision; This product is suitable for dairy, food, beer, beverage, pharmaceutical, cosmetics and other industrial fields;

　　5. External processing: you can process non-standard products with drawings and samples according to user requirements;

　　6. Connection mode: clamp type, welding type and thread type.

　　Note that the pipe fitting reducer is also suitable for pipe reducing in the environmental protection and dust removal industry. It is generally made of rolled steel plate, cut and welded, with different pipe diameters and different materials

　　It is generally hot-rolled coil, which is applied very well and can save cost.

Causes of cracks during bend process

　Causes of cracks during bend process: defects and protection microcracks generated during medium frequency bending. When induction heating bend steel pipe, microcracks will be generated on the outside of the bend when the deformation temperature and deformation of a certain level are exceeded. Both of these conditions are related to the material of the bend pipe. Under the similar forming conditions of low deformation speed and high tension resistance, all bending construction of the pipe bend under this condition may produce such data damage. The domestic pipe bending market continued to decline. At the end of the month, there were signs of acceleration due to the broken position of pipe bend processing price. The social inventory of pipe bend continued to go through the process, and the Lange composite index closed below the 140 level.

　　As for microcracks, we stop the discussion with grain boundary cracks. According to the forming conditions, the crack length is generally reachable. The cracks mainly occur on the austenite grain boundary perpendicular to the stress direction, so they are also perpendicular to the slag inclusion of the extended pipe. After the welded pipe is bent, the microstructure is recrystallized by heat treatment, so that the microcrack changes into crystal.

Welding method of flange

The welding method of flange is left welding method, and the welding torch advances at a uniform speed to keep up and down without jumping. The welding wire is added from the front edge of the molten pool along the welded junction and close to the flange welded junction, and the amount depends on the gap and speed. Try not to add more frequently, so as to avoid the formation of weld concave during flange flat welding and weld convex during overhead welding. The principle is that the flange weld is formed at one time. The end of the welding wire is always within the scope of argon protection to avoid red hot end oxidation. The welding wire shall not extend into the molten pool to disturb the argon flow.

　　The diameter of welding wire is 2.0 ~ 2.5mm, the welding current is between 40 ~ 100A, the argon flow is 8L / min, the diameter of welding torch nozzle is 8mm, and the distance between nozzle and workpiece is 5 ~ 10mm.

　　Air supply 3 ~ 5S in advance during arc striking. Before arc extinguishing, the traveling speed shall be increased first, and then the arc shall be extinguished to eliminate the arc crater.

Basic introduction of elbow

Elbow in the pipeline system, elbow is a pipe fitting that changes the direction of the pipeline. According to the angle, there are three commonly used elbows: 45 ° and 90 ° 180 °, and other abnormal angle elbows such as 60 ° are also included according to the needs of the project. Elbow materials include cast iron, stainless steel, alloy steel, malleable cast iron, carbon steel, non-ferrous metals and plastics. The connection methods with the pipe include: direct welding flange connection, hot-melt connection, electric fusion connection, threaded connection and socket connection, etc. According to the production process, it can be divided into: welding elbow, stamping elbow, push elbow, casting elbow, butt welding elbow, etc. Other names: 90 degree elbow, right angle bend, love bend, etc.

Elbow is a commonly used connecting pipe fitting in plumbing installation. It is used for the connection at the bend of the pipeline and to change the direction of the pipeline.

Other names: 90 ° elbow, right angle bend, love bend, stamping elbow, machine-made elbow, welding elbow, etc.

Purpose: connect two pipes with the same or different nominal diameter to make the pipeline turn 90 °, 45 °, 180 ° and various degrees.

Bending radius less than or equal to 1.5 times of pipe diameter belongs to elbow, and bending radius greater than 1.5 times of pipe diameter belongs to elbow.

A connecting pipe fitting commonly used in pipeline installation, which connects two pipes with the same or different nominal diameter to make the pipeline turn at a certain angle, and the nominal pressure is 1-1.6mpa.

Production and processing method of pipe tee

1. Forging

That is to use forging machine (rotary type, connecting rod type and roller type) to punch and stretch the end or part of the pipe to reduce the outer diameter.

2. Stamping

The taper core is used to expand the pipe end to the required size and shape. This operation is carried out on the punch.

3. Roller

For round edge processing, place the core in the pipe and press the outer circumference with rollers.

4. Rolling

It is suitable for the inner round edge of thick wall pipe. Generally, there is no mandrel.

5. Bulging

The rubber is mainly put into the tube and compressed with a punch at the top to make the tube protrude and form; Filling the middle of the pipe with liquid and bulging the pipe into the required shape by the pressure of the liquid.

In addition, there is another processing method of using mold to produce pipe tee. The mold includes upper mold and lower mold. The lower die is provided with a processing cavity, the upper die is provided with a processing block matching the shape of the processing cavity, and the processing cavity is a horizontal T-shape. In addition to the T-shaped intersection, the cross-section intersection of the processing cavity is semicircular, and the opening of the cross-section is located on the upper surface of the lower die, which changes the processing mode of the tee pipe and processes two semicircular tee pipe fittings one by one. The opening of the pipe joint is welded to increase the contact surface between the two and reduce the difficulty of welding. In addition, the semicircular tee fitting is easy to be placed on the ground without swinging, which further improves the processing stability. It avoids the situation that the traditional nozzle is easy to roll in the processing process.

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