The alloy elbow

As a variety of elbow type alloy elbow bend is referred to, is used to bend pipe connections, is connected to two of the same nominal diameter tube, and make the line do turn 90 ° or other angles.It has a variety of materials, alloy elbow is very versatile.

Common bronze alloy elbow is more common in general tap water pipes, but with the improvement of living standard, many tap water pipes have changed to stainless steel elbow.

An overview of the

Manganese steel alloy material elbow as manganese steel can withstand shock, extrusion, material wear of excellent properties, such as is commonly used in the conveying pipe, mud pipeline etc wear consumption more serious in the pipeline.The high manganese steel alloy elbow is used in pipelines with strong impact and strong fluid flow.Nickel alloy steel quality bend are usually used in high concentration of oxidizing acid (nitric acid, sulfuric acid) at room temperature in the pipeline, but in reducing acid (hydrochloric acid, thin sulfuric acid, etc.) of severe corrosion in the pipeline will be, unless the hydrochloric acid concentration is very low;Martensitic alloy bend under 650 ℃ high temperature strength, oxidation resistance and water vapor corrosion resistant ability, but poor weldability.Therefore, it is often used in high temperature water vapor transmission pipeline, water gas pipeline.Performance standards: GB/ t12459-2005, GB/T13401, GB/ t10752-1999.

Production methods

Push hot forming

Hot push bend forming technology is to use special elbow push system core machine, mold and heating device, to set on the mould of billet in pushing forward movement, under the impetus of the machine in motion is heated and hole enlargement and forming process.Hot push bend deformation characteristics are based on volume before and after plastic deformation rule of metal materials determine the pipe diameter, pipe diameter bend diameter, through the core module and control the deformation of the process, make the inner arc compressed metal flow, the compensation to other parts of the thinned by hole diameter, wall thickness uniform Angle is obtained.

Hot push bend forming technology has a good appearance, uniform wall thickness and continuous operation, suitable for the characteristics of mass production, thus become the main forming methods of carbon steel, alloy steel elbow, and also the application in some of the specifications of the stainless steel elbow forming.

Forming process of the heating mode with intermediate frequency or high frequency induction heating (heating can be multiple times or lap), flame heating and reverberatory furnace heating, adopt what kind of heating mode according to the condition of forming product requirements and energy.

stamping

Stamping elbow is first applied to the forming process of the mass production of seamless elbow, the commonly used in the production of the specifications of the elbow has been replaced by a hot method or other forming process, but in some of the specifications of the elbow because of less production quantity and wall thickness too thick or too thin.

The product is still in use when there are special requirements.The press machine is used to press the pipe blank with the same diameter as the outside of the elbow directly in the mould.

Before stamping, the billet is placed on the lower die, and the inner core and end die are loaded into the billet. The upper die moves downward and starts to be pressed. The elbow is formed by the constraint of the outer die and the support of the inner die.

Compared with hot extrusion process, the appearance quality of stamping forming is inferior to that of the former.The outer arc of the stamping elbow is in a state of stretching when it is formed, and there is no excess metal in other parts to compensate, so the wall thickness at the outer arc is reduced by about 10%.However, because it is applicable to single part production and low cost, the stamping elbow technology is mainly used in the manufacture of small batch and thick wall elbow.

The stamping elbow is divided into two types: cold stamping and hot stamping, usually cold stamping or hot stamping according to the nature of materials and equipment capability.

Cold extrusion of bend forming process is the use of dedicated elbow forming machine, pipe to be included in the external formwork, upper and lower mould clamping, under the impetus of the push rod, tube billet model along the internal model and reserved clearance sports and forming process.

Using die cold extrusion process inside and outside the elbow and good appearance, uniform wall thickness, size deviation is small, so for the stainless steel elbow especially thin wall stainless steel elbow forming more made by this technology.The precision of internal and external dies used in this process is high.The deviation of wall thickness of billet is also strict.