A Ni-Cr-Mo alloy used in the most corrosive environments
- Excellent corrosion resistance to reducing and oxidizing environments
- Well suited for hydrochloric and sulfuric acid environments
- Strong resistance to stress corrosion cracking
- Excellent mechanical properties at elevated temperatures
- Alloy grades: C276, B2, B3, C22, C2000, Hastelloy X
- Hastelloy 12 point screw features and benefits
Hastelloy® 12 point screws are in stock and available now - such as Hastelloy C276, which is generally considered a versatile and highly corrosion resistant alloy. Hastelloy screws have excellent corrosion resistance in both oxidizing and reducing media which makes it well suited for a variety of strong corrosive applications. Hastelloy screws also have exceptional resistance to both sulfuric acid and hydrochloric acid.
Because Hastelloy 12 point screws resist some of the most severe media, Hastelloy screws are often utilized in chemical processing applications where acid chlorides, solvents, formic and acetic acids, acetic anhydride, wet chlorine gas, hypochlorites, chlorine solutions and phosphoric acid are used. For chemical processing applications, Hastelloy C276 is the most common grade and one of the most corrosion resistant nickel alloys - exceeding that of most other nickel alloy grades like Inconel or Monel.
Hastelloy is available in several grades. For more indepth information on these specific grades, visit our specific web pages or contact one of our engineering experts:
Resources: Hastelloy Torque Spec
The driver of a Hastelloy 12-point screw uses two overlapped hexagon shapes, creating 12-points and a flanged underside. These are also referred to as ferry cap screws or 12 point flange screws. The advantages of this head style include:
- Higher torque capability compared to a socket head cap screw
- Lack of recess to trap fluid or debris.
- As the heads are generally smaller than a hex, Hastelloy 12-point screws are often used situations where installation space is tight and saving weight is critical.
The overall disadvantage is the extra cost involved in forming the heads.
The Controversy of 6 vs. 12 point Bolts
There is much debate over which bolt is better. Some say that the more points a nut or bolt has – such as a 12-point bolt - the less chance you have to round it off. And that the additional contact points of a 12 point screw give you more surface to apply load. While the jury is out as to the accuracy of this, it’s the application that should dictate whether the benefits of a 12 point screw out weight the additional costs of making them.
C276 alloy, UNS N10276, is the most widely used and versatile, corrosion resistant alloy. Very good resistance to reducing, and mildly oxidizing corrosives. Excellent stress corrosion cracking resistance with very good resistance to localized attack.
Hastelloy C276 Specifications: N10276, ASTM B574, ASME SB574, Werkstoff 2.4819, ASTM G28-A/B, EN 10204-3.1, ASME B18.2.2, ASTM B619, ASME SB619, ASTM B366, ASME SB366, WPHC276, ASME B16.11, ASTM B564/ASME SB564, COLD DRAWN, HOT FINISHED, ASTM B575, ASME SB575, COLD ROLLED, HOT ROLLED, ASME B16.9, ASME B16.5, ASTM B462, ASME SB462
B3 alloy, UNS N10665, resistance to hydrochloric acid and other strongly reducing chemicals but has poor corrosion resistance to oxidizing chemicals and in the presence of ferric or cupric salts. In addition, Hastelloy B2 has excellent resistance to pitting and stress corrosion cracking. However B2 has little chromium, and it should NOT be used with oxidizing media in the presence of salts.
Hastelloy B2 Specifications: N10665, ASTM B619, Werkstoff 2.4617, ASME SB619, ANNEALED, B/SB619 CLASS I OR II, X-RAY PER ASME SECTION VIII DIVISION 1 UW-51, MERCURY FREE, EN 10204-3.1, ASTM B366, ASME SB366, WPHB2-S, ASME B16.11, ASTM B335, ASME SB335, ASME B16.3, MSS SP-83, ASTM B564/ASME SB564, COLD DRAWN, HOT FINISHED, ASTM B333, ASME SB333, SHEET IS COLD ROLLED, HOT ROLLED, ENIMO-7, AWS A-5.11, ASME SFA-5.11
B3 alloy, UNS N10675, is specifically designed to deal with very aggressive hydrochloric acid (HCl), hyrdrobromic acid (HBr) and sulfuric acids (H2SO4) as well as acetic, formic and phosphoric acids. Additionally Hastelloy B3 has improved structural integrity over B2. However B3 has little chromium, and it should NOT be used with oxidizing media in the presence of salts.
Hastelloy B3 Specifications: N10675, ASTM B366, ASME SB366, Werkstoff 2.4600, WPHB3-W, ASME B16.9, ANNEALED, MERCURY FREE, EN 10204-3.1 (W/O X-RAY), ASTM B335, ASME SB335, ASTM B564, ASME SB564, DIMENSIONS PER ASME B16.5, ASTM B462, ASME SB462, ASME B16.5, COLD DRAWN, HOT FINISHED, ASTM B626, ASME SB626, B/SB626 CLASS III, ASTM B333, ASME SB333, COLD ROLLED, HOT ROLLED
C22 alloy, UNS N06022, has better overall corrosion resistance in oxidizing corrosives than C-276 and Inconel 625 alloys due to the higher chromium content. Outstanding resistance to localized corrosion and excellent resistance to stress corrosion cracking. This alloy has limited availability and can be made into fastener in larger diameters only (1/2" and greater in size).
Hastelloy C22 Specifications: SB 575/B 575, SB 574/B 574, SB 366/B 366 SB 462/B 462, SB 564/B 564 SB 462/B 462, Werkstoff 2.4602, 17744 No. 2.4602 NiCr21Mo14W, NACE MR0175 ISO 15156
C2000 alloy, UNS N06200, is a corrosion resistant alloy with excellent resistance to uniform corrosion in oxidizing or re-ducing environments. Due to the addition of copper and the high content of chromium, it has enhanced corrosion resistance to sulfuric acid and process streams contaminated with ferric ions. In addition it has excellent resistance to stress corrosion cracking and superior resistance to localized corrosion as compared to C-276 alloy. This alloy has limited availability and can be made into sizes only 1/2" and greater is size for fasteners.
Hastelloy C2000 Specifications: SB 575/B 575, SB 574/B 574, SB 366/B 366 SB 462/B 462,SB 564/B 564 SB 462/B 462, Werkstoff 2.4675, NACE MR0175 ISO 15156
Alloy X, UNS N06002, is most known for its exceptional combination of high temperature oxidation resistance up to 2000°C and high temperature strength. Being stable, strong and ductile at high temperatures are its most notable characteristics which is often utilized in gas turbine components and furnace components.
Hastelloy X Specifications: AMS 5536, AMS 5754, AMS 5798, ASME SB 435, ASME SB 572, ASME Sect. IX P No. 43, ASME Section IX P No. 43, ASME SFA 5.14, ASTM B 435, ASTM B 572, EN 2.4665, GE B50A436, GE B50T83, GE B50TF24, PDS 1038 (X-low), PDS 15102QFC, UNS N06002, Werkstoff 2.4665