Stainless steel pipe annealing after the brightness determines the quality of the product. The impact of factors are more, of which five most important factors are as follows: 1. Does the annealing temperature reach the specified temperature? Stainless steel heat treatment is generally taken to solve the heat treatment, which is commonly known as the "annealing", the temperature range of 1040 ~ 1120 ℃ (Japanese standard). You can also observe the hole through the annealing furnace observation, the annealing area of stainless steel pipe should be incandescent state, but did not appear softening sagging. 2. Annealing atmosphere. Generally, pure hydrogen is used as the annealing atmosphere. The purity of the atmosphere is preferably over 99.99%. If the other part of the atmosphere is inert gas, the purity can be lower, but it can not contain too much oxygen and water vapor. 3. Furnace sealing. Bright annealing furnace should be closed, and the outside air isolation; the use of hydrogen as a protective gas, and only one exhaust port is through (to ignite the discharge of hydrogen). Check the method can be used soap water wiped in the various joints of the annealing furnace joints to see whether the run gas; one of the most easy to run the place where the furnace into the pipe and the place where the pipe, the place of the ring is particularly vulnerable to wear, Always check for regular changes. 4. Protection of gas pressure. In order to prevent the occurrence of micro-leakage, the furnace to protect the gas should maintain a certain positive pressure, if it is hydrogen protection gas, generally require more than 20kBar. 5. Furnace water vapor. On the one hand to check the furnace material is dry, the first furnace, the furnace material must be dried; the second is into the furnace stainless steel pipe is too much residual water stains, special pipe above if there are holes, then do not leak into, Or else put the stove atmosphere all destroyed. To pay attention to these are basically these, normal, then should be back after the opening of about 20 meters of stainless steel pipe will begin to shine, the kind of reflective light.

The purpose of pipe end sizing is to reduce the ellipticity of steel pipe to ensure that the steel pipe after machining the dimensional accuracy, mainly for oil casing. After the end of the diameter of the casing, the end of the car when the black leather buckle (leaving the leakage surface of the thread) a small number, can improve the finished product rate. Pipe end sizing is a cold deformation process, the commonly used sizing method has a punch diameter and punch diameter + diameter ring compression two. The effect of reducing the ellipticity of the pipe when the punch is enlarged depends to a large extent on the uniformity of the wall thickness of the pipe. On the uneven thickness of the hot rolling pipe, such as the cycle of rolling mill rolling pipe (see the cycle of rolling mill rolling mill), the punch after the expansion of the pipe surface quality deterioration. Therefore, in order to eliminate the influence of uneven wall thickness and reduce the ellipticity of steel pipe, should adopt the punch diameter + sizing ring compression method. As the cold diameter, the tube end not only produce elastic deformation but also a small amount of plastic deformation. After the sizing, there may be different degrees of residual stress in the transition zone with diameter and non-expanding diameter, and the internal and external surface scratches caused by the punch and the sizing ring may occur, resulting in slight stress corrosion. Therefore, try to improve the dimensional accuracy of hot-rolled steel pipe, to avoid the use of pipe diameter method.

Seamless steel pipe cutting the main way to cut off the machine, machine cutting, flame cutting, sawing and so on. (1) Pipe cutting machine Pipe cutting machine equipment is simple, less investment, the application of a wide range, and some also has a groove function and automatic loading and unloading materials and aggregate devices. Pipe cutting machine is a commonly used equipment for seamless steel pipe finishing line. (2) Pipe saws Can be divided into row pipe saw, band saw and circular saw several forms. Pipeline saws can be cut into multiple rows of steel pipe, high production efficiency, but the equipment structure is complex, high investment; band saw and circular saw production efficiency is low, less investment. The circular saw is suitable for cutting off steel pipes with smaller outer diameters, while band saws are used to cut off steel pipes with larger outer diameters. (3) Flame cut off Flame cut off, including oxygen cutting, hydrogen and oxygen cutting and plasma cutting, the cutting method is more suitable for large diameter, thick wall seamless steel pipe cutting. When the plasma is cut, the cutting speed is faster. Due to the high temperature of the flame cutting, there is a heat affected zone near the incision and the port surface is not smooth. (4) Machine cut off This cut off the efficiency is very low, generally used for sampling and sample preparation.

1. Extruded parts size accurate surface smooth: the current development of China's cold extrusion parts of the general size of the accuracy of up to 8 to 9, if the ideal lubrication, the accuracy after the polished surface. So the cold extrusion method to create the parts, generally do not need to re-processing, a small amount of only finishing (grinding). 2. Save raw materials: cold extrusion material utilization rate can usually reach more than 80%. Such as Jiesuo brand car piston cutting processing material utilization rate of 43.3%, while the use of cold extrusion material utilization rate increased to 92%; and if the universal joint bearing sets to use cold extrusion, the material utilization from the past 27.8% to 64%. It can be seen that the use of cold extrusion method to produce mechanical parts, can save a lot of steel and non-ferrous metal materials. 3. High productivity: the efficiency of the production of mechanical parts with cold extrusion is very high, especially the production of large quantities of parts, with cold extrusion method to produce comparable cutting several times, several times, or even hundreds of times. For example, the car piston pin with cold extrusion method than cutting with manufacturing to improve 3.2 times, and now with cold extrusion piston pin automatic machine, so that productivity is further improved. The productivity of a cold extrusion robot is equivalent to the productivity of 100 ordinary lathes or 10 four-axis automatic lathes.

Buried steel pipe corrosion is to ensure and extend the life of the key procedures, in order to ensure that the anti-corrosion insulation layer and the wall with a solid, pipe rust is the most critical. Generally according to the factory time, storage of transport conditions, the degree of wet climate, steel pipe rust can be divided into floating rust, rust and rust. Floating rust: general factory date is shorter, non-open storage, only a small amount of thin rust on the surface of the pipe, can be used wire brush, sandpaper and cotton yarn and other manual operation that exposed metal luster. Rust and rust: the factory date is longer and open storage or multiple transshipment and transport longer, the pipe surface oxidation rust, the rust is heavy, serious decline in oxide scale. Severe corrosion of the pipeline is not suitable for sub-water delivery system, the rust pipe and large batch, the use of rust or mechanical sandblasting and other methods of mechanical rust, can improve labor efficiency and reduce the pollution of people and the air. When the requirements of high corrosion resistance or pipe wall are rusted, the use of chemical rust method, can effectively remove the tube inside and outside the surface of the oxide. Regardless of which method of rust, should be rusted immediately after the anti-corrosion treatment, to avoid once again by the air oxidation and corrosion.