A Ni-Cr alloy with very good high temperature stability

Not to be confused with Inconel, Incoloy vented screws are made of a nickel alloy which contains iron and a lower content of nickel. Incoloy is essentially a more economical option to Inconel, yet with more restricted corrosion resistance and temperature limits. Typically, Incoloy is an ideal material for long-term exposure in high temperature environments due to its oxidation, carburization and creep resistance. Incoloy is widely used for its resistance to seawater, brine, sour gas and high chloride environments at elevated temperatures, which make it a popular choice in the oil and gas and power industries. 

The most commonly used grades of Incoloy screws are Incoloy 800, 800H, 800HTIncoloy 825; and Incoloy 925. For more indepth information on these specific grades, visit our specific web pages or contact one of our engineering experts:

ResourcesIncoloy Torque SpecsFlange DimensionsFlange Bolting Chart

Incoloy Fastener Types: BoltsNutsScrewsThreaded RodsWashers

Screw Types Available:  12 Point ScrewsButton Head Cap ScrewsFlat Head ScrewsHex Head Cap ScrewsPan Head ScrewsSet ScrewsSocket Head Cap ScrewsTorx Screws


Incoloy Vented Screw Features & Benefits

Incoloy vented screws are ideal for use in high vacuum (UV) and ultra high vacuum (UHV) equipment, as well as other high pressure environments and applications where gas pockets can form. Center vented screws have a center bore drilled through their axis from the head through the threaded shank of the screw. This feature provides an outlet for the complete evacuation of trapped air and gas contaminants to be pumped away from blind-tapped screw holes, bottoms, sides and shoulders. In addition to vented screws, washers with vent grooves can be made to ensure the venting of the cavity found under the screw head.

Incoloy Vented Screws Benefits
•  Enables faster, more efficient pump-down of HV & UHV systems
•  Eliminates virtual leaksVented Screw TextCrop
•  Relieves pressure from blocked gases
•  Provides means to vent contaminants found in screw voids
•  Promotes higher system throughput and improved yield
•  Allows for constant pressure and temperature equalization

Incoloy Vented Screws Are Available In:
Grades:  Incoloy 800HT, Incoloy 825, and Incoloy 925
Styles:  Socket Head Cap Screw and Hex Head Cap Screw

vented washer

What is a vented washer?
When a screw is tightened over a flat washer, or directly an application without a washer, volumes of gas can be trapped in the space and beneath the fastener head along the screw shaft. Vented washers feature two bored canals on opposite sides of the flat face which provide an escape route for trapped gases.  

What is a virtual leak?
A virtual leak is comprised of gases that are trapped physically within a pocket with only a miniscule escape path from the trapped pocket of gas into the chamber proper. 


Common Incoloy Chemistry, Grades & Specifications

Incoloy 800, 800H, H00HT

Incoloy 800 series screws are best utilized for applications that require stable structure and good strength during prolonged exposure to high temperatures. 

Incoloy 800, 800H & 800HT Specifications: UNS N08800/ N08810 / N08811 (800, 800H, 800HT), ASTM B408, ASME SB408, ASTM B564/ASME SB564, EN 10204-3.1, Werkstoff 1.4876 (800), Werkstoff 1.4876 H and 1.4958 (800H), Werkstoff 1.4876 HT and 1.4959 (800HT)

 Incoloy 800 Chemistry

Incoloy 825

Related to the Incoloy 800 series alloys, Incoloy 825 differentiates itself with the additional elements of molybdenum and copper, which provides it improved corrosion resistance. 

Incoloy 825 Specifications: UNS N08825, , BS 3076NA16, ASTM B 425, ASTM B 564, ASME SB 425, ASME SB 564, ASME Code Case N-572, DIN 17752, DIN 17753, DIN 17754, VdTÜV 432, ISO 9723, ISO 9724, ISO 9725, Werkstoff Nr 2.4858

Incoloy 825 Chemistry

Incoloy 925

Incoloy 925 is a precipitation hardened alloy. It offers comparable corrosion resistance to it’s sister alloy Incoloy 825, but with the increased strength resulting from the age hardening process. 

Incoloy 925 Specifications: UNS N09925, ASTM B637, NACE MR0175 Incoloy 925 Chemistry


Mechanical Properties of Incoloy

Incoloy 800 Tensile Curve

Incoloy 825 Tensile Curve

  

 

Incoloy 925 Tensile Curve Aged 

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