VDM Alloys 22 Flanges

Suppliers, Manufacturers & Distributor in India.

VDM Alloy 22 Flanges is a nickel-chromium-molybdenum alloy with tungsten and extremely low carbon and silicon content supplied, manufactured & distributed by Sailesh Metal Corporation.

VDM Alloy 22 Flanges is characterized by:

• Extraordinary resistance across a wide range of corrosive media under oxidizing and reducing conditions
• Particularly high resistance to crevice, pitting, and stress corrosion

Properties of VDM Alloy 22 Flanges

Electrical
Electrical resistivity [ ρel ]	1.14E-6 Ω·m at 20 °C

 

General information
Density [ ρ ]	8.70 g/cm³

 

Mechanical
Elastic modulus [ E ]	206.00 GPa at 20 °C
Elongation A50 [ A50 ]	45.00 %
Hardness, Brinell [ HB ]	240.00 [-]
Impact strength, Charpy notched [ Ivnot ]	1500 kJ/m²
Tensile strength [ Rm ]	690.00 MPa
Yield strength Rp0.2 [ Rp0.2 ]	310.00 MPa at 20 °C
Yield strength Rp1.0 [ Rp1.0 ]	290.00 MPa at 100 °C

 

Thermal
Coefficient of thermal expansion [ α ]	1.24E-5 1/K at 100 °C
Melting point [ Tm ]	1355—1400 °C
Specific heat capacity [ cp ]	406.00 J/(kg·K) at 20 °C
Thermal conductivity [ λ ]	9.40 W/(m·K) at 20 °C

All metrics apply to room temperature unless otherwise stated. SI units used unless otherwise stated.

Chemical composition of VDM Alloy 22 Flanges:

Element	Weight %
Ni	—	balance
Cr	20.0 — 22.5
Mo	12.5 — 14.5
Fe	2.0 — 6.0
W	2.5 — 3.5
Co	2.5
Mn	0.5	max
V	0.35	max
Si	0.08	max
P	0.025	max
S	0.015	max
C	0.01	max

Corrosion resistance

Due to the extremely low carbon and silicon concentrations, VDM Alloy 22 has no propensity for grain boundary dispersions in hot forming or welding. This alloy can therefore be used in many chemical processes with both oxidizing and reducing media when welded. The high chrome, molybdenum, and nickel concentrations make the alloy resistant to chloride-ion attacks. The tungsten concentration further increases this resistance. VDM Alloy 22 is resistant to chlorine gas, hypochlorite, and chlorine dioxide solutions such as those that can be encountered in the cellulose industry. The alloy is characterized by excellent resistance to concentrated solutions of oxidizing salts (such as iron III and copper chloride).

Applications

VDM Alloy 22 has a broad field of application in the chemicals and petrochemicals industry and is used for components in organic processes that contain chloride and for catalytic systems. The material is especially effective in hot, contaminated mineral acids, solutions, organic acids (such as formic acid and acetic acid) or sea water. Other fields of application are:

Acetic acid production

Pharmaceuticals industry

Fine chemicals

Fabrication and heat treatment

VDM Alloy 22 Flanges can be easily formed both hot and cold and can also be machined

Heating

It is important that the workpieces are clean and free of any contaminations before and during heat treatment. Sulphur, phosphorus, lead and other low-melting point metals can result in material damage during the heat treatment. This type of contamination is also contained in marking and temperature-indicating paints or pens, and also in lubricating grease, oils, fuels and similar materials. The sulphur content of fuels must be as low as possible. Natural gas should contain less than 0.1 wt.-% of sulfur. Heating oil with a maximum sulfur content of 0.5 wt.-% is also suitable. Electric furnaces are preferable for their precise temperature control and a lack of contaminations from fuels. The furnace temperature should be set between neutral and slightly oxidizing and it should not change between oxidizing and reducing. The workpieces must not come into direct contact with flames.

Hot forming

The material can be hot-formed in a temperature range between 1,100 and 900 °C (2,012 °F-1,652 °F) with subsequent rapid cooling down in water or air. Heat treatment after hot forming is recommended in order to achieve optimal properties. For heating up, workpieces should be placed in a furnace that is already heated up to the target value.

Cold forming

VDM Alloy 22 has higher work hardening rate than other austenitic stainless steels. This should be taken into account when selecting forming equipment. The workpiece should be in the solution-annealed condition. Intermediate annealing is necessary for major cold forming work. For cold forming above 15%, new solution annealing must be conducted.

Heat treatment

Solution annealing should take place at temperatures between 1,105 and 1,135 °C (2,021-2,075 °F). Cooling down should be accelerated with water to achieve optimum corrosion properties. Fast air cooling can also be carried out at thicknesses of less than approx. 1.5 mm. For strip and wire products, the heat treatment can be performed in a continuous furnace at a speed and temperature that is adapted to the material thickness. In each heat treatment, the aforementioned cleanliness requirements must be observed.

Descaling and pickling

Oxides of VDM Alloy 22 and heat tint in the area around welds adhere more strongly than in stainless steels. Grinding using extremely fine abrasive belts or grinding discs is recommended. It is imperative that grinding burns be avoided. Before pickling in nitric-hydrofluoric acid, the oxide layers should be destroyed by abrasive blasting or fine grinding, or pre-treated in salt baths. The pickling baths used should be carefully monitored with regard to concentration and temperature.

Machining

VDM Alloy 22 should be machined in the solution-annealed condition. Because of the considerably elevated tendency toward work hardening in comparison with low-alloy austenitic stainless steels, a low cutting speed and a feed level that is not too high should be selected and the cutting tool should be engaged at all times. An adequate chip depth is important in order to cut below the previously formed strain-hardened zone. An optimal heat dissipation by using large quantities of suitable, preferably aqueous, cold forming lubricants has considerable influence on a stable machining process.