ASME B16.20 Hastelloy C276 Spiral Wound Gaskets
Hastelloy C276, Alloy 276 (UNS N10276), A Nickel-Base Alloy with Resistance in a Wide Range of Aggressive Media.
Alloy 276 is a nickel-molybdenum-chromium-iron-tungsten alloy which is among the most corrosion resistant alloys currently available. Alloy 276 also has good high temperature strength and moderate oxidation resistance although the alloy will eventually form embrittling high temperature precipitates. Alloy 276 has been available for several years and has been used in ASME Boiler and Pressure Vessel related construction.
Spiral Wound Gasket C276 Style applications:
> Chemical and petrochemical processing;
> Flue gas desulfurizationg;
> Pulp and paper equipments;
> Industrial and municipal waste equipments.
General Corrosion:
> The alloy 276 is used in a range of environments from moderately oxidizing to strongly reducing;
> One application is in the more corrosive area of flue gas desulfurization system, such as outlet ducting;
> Alloy 276 compared to that of SS316 in the “GREEN DEATH” simulated scrubber solution
|
Green Death Solution (Boiling) |
Corrosion Rate, MPY (mm/a) |
|
|
|
316 |
276 |
|
3% Hydrochloric Acid |
Destroyed |
26.5 (0.67) |
> Alloy 276 is considered inert to seawater and is used in many seawater, brine, and high chloride environments, even at strong acid pH values;
> The high level of nickel and molybdenum provides extreme resistance to chloride stress corrosion cracking.
Chemical Analysis:
|
C |
Mn |
P |
S |
Si |
Cr |
Ni |
Mo |
W |
V |
Co |
Fe |
|
0.006 |
0.150 |
0.005 |
0.002 |
0.03 |
15.50 |
Balance |
16.0 |
3.50 |
0.15 |
0.10 |
6.00 |
Mechanical Properties:
Minimum properties (ASTM B 575)
|
0.2% Yield Strength Minimum psi (MPa) |
Ultimate Tensile Strength Minimum psi (MPa) |
Elongation (% in 2”) Minimum |
Hardness Rb Minimum |
|
41,000 (283) |
100,000 (690) |
40 |
100 |
Density: 0.321lb/in3, 8.90g/cm3
Specific Gravity: 8.90
Specific Heat: 0.102 Btu/lb/oF, 425 Joules/kg/oK
Magnatic Permeability: 1.02
Electric Resistivity: 130 microhm-cm at 23 oC
Elastic Modulus 21oC: 29.8×106 psi (205 GPa)
Descaling and Cleaning:
Clean surface is required to obtain the optimum corrosion resistance of C276. The alloy 276 content of the materials makes descaling difficult. Stainless wire brushing or grit blasting is advisable, followed by immersion in a mixture of nitric and hydrofluoric acids and a thorough water rinse.
C276 Spiral Wound Gaskets styles:
> SW600-276-R: C276 Strip, Graphite Filler or PTFE Filler, 276/FG or 276/PTFE;
> SW600-276-CG: C276 Strip, Graphite or PTFE filler, C276, SS, or CS outer ring, 276/FG-CS;
> SW600-276-CGI: C276 inner ring, C276 Strip, Graphite or PTFE filler, C276, SS, or CS outer ring, C276-276/FG-CS;
> SW600-276-RIR: C276 inner ring, C276 strip, Graphite or PTFE Filler, Without outer ring, C276-C276/FG;
Other styles according to requirements.
Spiral Wound Gasket is Filler materials used are Graphite, Non asbestos material, PTFE..Inner & Outer Rings are also used as per customer specifications.
ASME B16.20 Spirak Wound Gasket, which is sophistically made by spirally winding a pre-formed metal strip and stuffing on the external periphery of metal winding mandrels. Moreover, our gaskets find extensive application in oil refineries power plants, petro chemical industries and marine fertilizer industries. Further, these spiral wound metallic gaskets are well known for its strength and brilliant performance.
