Bumax grades

BUMAX 88 is a premium A4 fastener that offers better corrosion resistance than standard A4 due to higher molybdenum content. The PRE value of Bumax 88 is 27 and of a standard A4 only 23. Bumax 88 offers higher strength and lower amount of inclusions than standard A4 fasteners, that gives superior mechanical properties and fatigue resistance and less variations compared to standard A4. Bumax 88 fasteners are used in many applications that demands very low magnetic permeability, it has lower magnetic permeability and less variation from batch to batch compared to standard A4 fasteners. Bumax 88 is also widely used in cryogenic applications down to -269°C (4 K) and can also be provided with a pre-approval PMA for PED certificate for pressure vessels. We have a large selection in stock for same day delivery from our warehouse.

BUMAX 109 is the strongest A4 fastener on the market. We use the same material as Bumax 88 but achieve higher strength due to a special manufacturing process. We have a large selection in stock for same day delivery from our warehouse.

BUMAX Nitro, an austenitic stainless steel with high nitrogen content, characterized by very high strength and fatigue resistance, in combination with good corrosion resistance. It is an excellent choice for marine applications and can be supplied in strength class up to 12.9. PRE value 35. Can be supplied on demand.

BUMAX Super Austenite (SA), Grade EN 1.4547; UNS S31254 (254 SMO) is a 6Mo high-alloy austenitic stainless steel for seawater and other aggressive chloride bearing medias. Excellent resistance to general, crevice, pitting and stress corrosion with a PRE value of 43. Strength class up to 10.9. Can be supplied on demand.

BUMAX Lean Duplex (LDX), Grade EN 1.4162; UNS S32101 (LDX 2101) offers an economical solution for high strength fasteners (up to 12.9) in low -medium corrosive environments. PRE 26. Can be supplied on demand.

BUMAX Duplex (DX), Grade EN 1.4462; UNS S32205 (2205) is characterized by excellent strength, ductility and fatigue resistance in combination with good general, pitting, crevice and stress corrosion properties. Strength class up to 12.9 with an excellent ductility giving an elongation of >0,3 x diameter and PRE >34. We have a large selection in stock for same day delivery from our warehouse.

BUMAX Super Duplex (SDX), Grades EN 1.4410, UNS S32750 & EN 1.4501, UNS S32760; is characterized by excellent mechanical properties and very good corrosion resistance. Excellent resistance to general crevice, pitting and stress corrosion in chloride bearing medias with a PRE of 42. Strength class up to 12.9 with an excellent ductility giving an elongation of >0,3 x diameter. We have a large selection in stock for same day delivery from our warehouse. We also have stocks of fasteners according to NORSOK M-650 D60.

BUMAX Hyper Duplex (HDX), Grade EN 1.4658, UNS S32707; a groundbreaking alloy used in the most demanding applications. Suited for use in severe corrosive environments such as hot chlorinated sea-water and for aggressive acidic chloride containing media in chemical, oil & gas, marine and petrochemical industry. PRE 49 and can be supplied on demand.

BUMAX Ultra, a unique precipitation hardenable stainless steel that can be delivered in ultra-high strength levels. Offers a unique combination of ultra-high strength combined with excellent ductility and good corrosion resistance in chloride environments, PRE 25. Strongest stainless steel fastener on the market with a strength class up to 16.9. Can be supplied on demand.

BUMAX Heat (HE), Grade EN 1.4980, UNS S66286 (A286); a high temperature resistant material for applications requiring high strength and good oxidation resistance at temperatures up to 700°C. Can be precipitation hardened.

BUMAX Heat Plus (HEP), Grade EN 2.4952, UNS N07080 (Nimonic 80). A nickel base alloy which is a precipitation hardenable high temperature resistant material with excellent oxidation resistance and high tensile and creep properties at temperatures up to 815°C.

 

Other special grades can be offered on request

 

Chemical composition

All values are nominal unless stated otherwise

 

Grades EN UNS Micro structure C max Cr Ni Mo Other PRE¹
BUMAX 88 1.4432, 1.4436, 1.4435 S31603 Austenitic 0.03 17 11.5 2.7 27
BUMAX 109 1.4432, 1.4436, 1.4435 S31603 Austenitic 0.03 17 11.5 2.7 27
BUMAX Nitro S31675 Austenitic 0.035 20.5 10 2.4 N 0.4, Mn 4 35
BUMAX SA 1.4547 S31254 Austenitic 0.01 20 18 6.2 N, Cu 43
BUMAX LDX 1.4162 S32101 Ferrite-Austenitic 0.03 21.5 1.5 0.3 N 0.22,Mn 5 26
BUMAX DX 1.4462 S31803, S32205 Ferrite-Austenitic 0.03 22 5.2 3.2 N 0.18 36
BUMAX SDX 1.4410 S32750 Ferrite-Austenitic 0.03 25 7 4 N 0.3 42
BUMAX HDX 1.4658 S32707 Ferrite-Austenitic 0.03 27 6.5 4.8 N 0.4, Co 49
BUMAX Ultra  S46910 Martensitic 0.02 12 9 4 Al, Ti, Cu 25
BUMAX HE 1.4980 S66286 Austenitic 0.08 15 26 1.5 Ti, V
BUMAX HEP  2.4952 N07080 Austenitic 0.10 19 >65 - Al, Ti, Co
Other grades can be offered on request
¹ PRE (Pitting Resistance Equivalent) number shows the pitting corrosion resistance of stainless steels. A higher PRE number indicates better corrosion resistance. The PRE is defined as, in weight-%: PRE= % Cr + 3.3 x % Mo + 16 x % N

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