Super Phosphoric Acid or what is shortened as SPA is a liquid with a P2O5 i.e. Phosphorus pentoxide concentration that ranges between 69% - 76%. SPA, like phosphoric acid, is a corrosive compound. Hence its production would require one of the stronger alloys. What better than Inconel 625 fasteners! Since bolts are used in the joining of pieces of equipment used in the production process of SPA, are exposed to the chemicals, Inconel 625 Bolts is often preferred by most manufacturers.
This is because this nickel containing Inconel 625 hex bolt performs admirably especially in the production of the third largest mineral acid commodity, i.e. - Phosphoric acid. During the wet processing of phosphoric acid, the Alloy 625 studs come in contact with certain impurities, which are in the form of sulfates, fluorides and fluosilicates. Being resilient to these compounds, the Alloy 625 forging promotes the smooth processing of phosphoric acid.
Additionally, since phosphoric acid does not degrade the ASTM B446 bolts, most manufacturers prefer using Inconel 625. Moreover, the longevity of the Inconel 625 nuts ensures that these are not replaced time and again thereby proving a cost saving alternative.
astm b446 bolts Sizes Metric
Alloy 625 Bolts
Size: 3/6" to 2" | M3 to M56 or Custom Sizes
Available Types Of Alloy 625 fasteners
inconel 625 threaded rod
alloy 625 washers
alloy 625 screws
Alloy 625 hex bolt
astm b446 bolts
Alloy 625 nuts
Alloy 625 forging
Inconel 625 Bolts can sustain upto 2200°F, so it is better option than any other alloy for bolting in furnace, Nuclear power, Marine, Oil and Gas. In this Grade of Nickel alloy the most common types are Stud Bolt, Hex Bolt and Threaded Rod.
Size Standard and Specification of Inconel 625 bolts
ASTM B446 /ASME SB446
all International Standards and ASTM, DIN, BS
Size in inches
3/6" to 2" | M3 to M56 or Custom Sizes Available as per requirement
supply Length Of Bolts
3 mm to 200 mm
Various Fasteners Type
Lag Bolts, Square nuts, U bolts, Hex Head nuts, Eye nuts, Lock nuts, T nuts, Eye bolts, wing nuts, Counter sunk Bolts, Coupling Nuts, Square Bolts, Panel Nuts, Hex Bolt, Acorn Nuts, T bolt, Dome nuts, Hex Head Bolts
Mechanical Properties Analysis of Alloy 625 hex bolt
Elongation (% in 50mm) minimum
Strength of Yield 0.2% Proof (MPa) minimum
Strength of Tensile (MPa) minimum
Rockwell B (HR B) maximum
Brinell (HB) maximum
Psi – 75,000 , MPa – 517
Psi – 1,35,000 , MPa -930
Chemical Compatibility Chart of Alloy 625 nuts
Equivalent grades table of Alloy 625 threaded rod
What is Inconel 625 bolts and nuts temperature range?
The Inconel 625 is a nickel chromium molybdenum columbium alloy that has high yield strength and tensile strength and it is produced in different forms. There are also bolts and nuts manufactured in this material. The Inconel 625 bolts and nuts can operate in the temperature range of cryogenic (-20 degrees) to above 1000 degrees Celsius. It is a huge advantage for these bolts and nuts to be used in applications that need to operate under deviating temperatures from cryogenic to elevated temperatures. The applications include heat exchangers, boiler components and super heater elements. There are different types and shapes of these bolts and nuts that can operate in this temperature range.