Angle Valve Is Introduced

- Apr 25, 2019-

concept

Angle valve is called again triangle valve, Angle form valve, fold Angle water valve, use at decorating the water and electricity installation of the industry more, it is important plumbing fittings.

The characteristics of

1, the flow path is simple, dead area and eddy current area is small, with the help of the medium itself scour effect, can effectively prevent the medium blocking, that is, a good self-cleaning performance;

2, the flow resistance is small, the flow coefficient is larger than the single-seat valve, equivalent to the flow coefficient of the two-seat valve;

It is suitable for high viscosity, suspension and granular fluid occasions, or for the requirements of right-angle pipe.The flow direction is generally bottom in and side out.

Special circumstances can be reverse loading, that is, the flow side into the bottom out.

Triangle valve cold and hot two kinds (with blue, red mark distinction) its material is the same as most manufacturers, cold and hot mark, mainly in order to distinguish which is hot water, which is cold water.

The production process

Raw materials (copper, steel, etc.) according to the material cut off high temperature forging machining polishing processing plating assembly.

The difference between

What is the difference between quick opening delta valve and ordinary delta valve:

One is rubber valve core, one is ceramic valve core, fast open is the latter, only 90 degrees can be done, commonly known as fast open type.Angle valves are also commonly used in gas cookers.

Use fixed number of year

Red stamping and forging in more than 10 years, 5-8 years of alloy molting about 3 years.Alloy 3 years or so will be very brittle, may break into the pipe and can not be replaced, copper is relatively easy to change.

The research background

More than 10,000 kitchen washing dishes produced by a sanitary ware enterprise were installed with brass Angle valves, which cracked after about 4 months of use.The Angle valve is installed below the dish washer, and the cracking position is at the pipe mouth of the pp-r joint.Angle valve material for HPb58-2 brass, chrome - plated surface.Figure 1 shows the appearance of cracked Angle valve. Serious deformation marks appear on the top of its screw teeth, and the chromium plating layer is extruded to reveal the copper matrix. This phenomenon is universal in cracked Angle valve

By means of fracture observation, chemical composition analysis, hardness test and metallographic examination, the cracking failure reason of brass Angle valve is analyzed, and improvement Suggestions are put forward to provide reference for the production and rational use of brass Angle valve.

Folded physical and chemical test

Fig.3 shows the typical macroscopic morphology of the crack Angle valve fracture. It can be seen that there is no obvious deformation at the fracture, the surface is covered with a layer of corrosion products, and the corrosion color of the inner wall surface is deeper than that of the outer wall surface, which indicates that the crack starts at the inner wall, that is, the crack expands from the inside to the outside.

FIG. 4 shows the microstructure of typical Angle valve fracture, showing typical cleavage fracture characteristics.The composition of corrosion products on fracture surface was analyzed by X-ray energy spectrometer.

The above fracture analysis results show that there is no obvious macroscopic deformation at the fracture of the Angle valve, the crack source is on the inner surface, the fracture microstructure is characterized by cleavage brittle fracture, and the corrosion products on the surface contain corrosive elements such as sulfur, oxygen and chlorine, which are all typical characteristics of stress corrosion cracking.This shows that the cracking of Angle valve belongs to stress corrosion cracking.

Metallographic examination of the section near the cracked Angle valve shows that the crack is bifurcated.This is a typical characteristic of stress corrosion cracking, which further indicates that the cracking of Angle valve belongs to stress corrosion cracking.

Folding synthesis

Hpb58-2 brass has good mechanical properties, processing properties and corrosion resistance. It is widely used in bathroom products, water supply and drainage pipes, MEDALS, serpentine pipes, condensing pipes, shell casings and various complicated shaped punching products and hardware.Brass has good corrosion resistance, but it is sensitive to stress corrosion cracking, especially brass with zinc content more than 15%(mass fraction).Therefore, it is necessary to eliminate stress treatment after brass forming to reduce stress corrosion cracking tendency.In terms of corrosive medium, brass is more sensitive to stress corrosion cracking of sulfur-containing corrosive medium. If there are corrosive elements such as sulfur, oxygen and chlorine in the environment, the occurrence of stress corrosion cracking will be accelerated.

By fracture analysis, metallographic examination and energy spectrum analysis, the Angle valve fracture did not see obvious macroscopic deformation, crack source in the inner surface, the crack is split, microscopic is cleavage fracture characteristics of brittle fracture, fracture surface corrosion products of the corrosive elemental sulfur, oxygen, chlorine, etc, these characteristics show that the Angle valve cracking belongs to the typical stress corrosion cracking.Stress corrosion cracking needs to satisfy two conditions, one is the corrosive medium, and the other is the role of stress, especially tensile stress, so it can be inferred that there is a certain tensile stress inside the cracked Angle valve.It is pointed out that the tensile stress often comes from welding, cold working, heat treatment and assembly.

The failure of Angle valve is a typical stress corrosion cracking, the main reason of which is that the assembly stress of Angle valve is too large.It is suggested that the assembly strength should be controlled when assembling the brass Angle valve to avoid leaving too much internal stress in the Angle valve and causing early failure of the Angle valve.