BUMAX 88 offers better corrosion resistance than standard A4 due to higher molybdenum content. Bumax 88 is a very consistent material that offers higher yield strength and lower amount of inclusion than standard A4 fasteners, that gives superior mechanical properties and fatigue resistance. 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 109 is the strongest A4 bolt on the market. Same material as Bumax 88 but higher strength due to special manufacturing process.BUMAX Nitro, austenitic stainless steel with high nitrogen content, characterized by very high strength and fatigue resistance, in combination with good corrosion resistance. Excellent material for marine application and can be supplied in strength class 12.9 up to M42.BUMAX Super Austenite (SA), high-alloy austenitic stainless steel for seawater and other aggressive chloride bearing medias. Excellent resistance to general, crevice, pitting and stress corrosion.BUMAX Lean Duplex (LDX) offers economical solution for high strength fasteners in medium corrosive environments.BUMAX Duplex (DX) are characterized by excellent strength, ductility and fatigue resistance in combination with good general, pitting, crevice and stress corrosion properties.BUMAX Super Duplex (SDX) are characterized by excellent mechanical properties and very good corrosion resistance. Excellent resistance to general crevice, pitting and stress corrosion in chloride bearing medias.BUMAX Hyper Duplex (HDX), 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.BUMAX Ultra, a unique precipitation hardenable stainless steel that can be delivered in ultra high strength levels. Offers an unique combination of ultra high strength combined with excellent ductility and good corrosion resistance in chloride environments. Strongest stainless steel fastener on the market.BUMAX Heat (HE), 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), 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 compositionAll values are nominal unless stated otherwiseGradesENUNSMicro structureC maxCrNiMoOtherPre¹BUMAX 881.4432, 1.4436, 1.4435S31603Austenitic0.031711.52.727BUMAX 1091.4432, 1.4436, 1.4435S31603Austenitic0.031711.52.727BUMAX NitroS31675Austenitic0.03520.5102.4N 0.4, Mn 435BUMAX SA1.4547S31254Austenitic0.0120186.2N, Cu43BUMAX LDX²1.4462S32101Ferrite-Austenitic0.0321.51.50.3N 0.22,Mn 526BUMAX DX1.4462S31803, S32205Ferrite-Austenitic0.03225.23.2N 0.1836BUMAX SDX1.4410S32750Ferrite-Austenitic0.032574N 0.342BUMAX HDX1.4658S32707Ferrite-Austenitic0.03276.54.8N 0.4, Co49BUMAX Ultra S46910Martensitic0.021294Al, Ti, Cu25BUMAX HE1.4980S66286Austenitic0.0815261.5Ti, VBUMAX HEP 2.4952N07080Austenitic0.1019>65-Al, Ti, CoOther grades can be offered on request¹ 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 % N² Standard offer for Bumax LDX is 1.4162 (PRE 26), but we have also the possibility to supply 1.4661 (PRE 33)

The majority of our fasteners are cold forged in our own facilities in Sweden where we have made cold forged stainless fasteners since 1926. Cold forging gives a superior product with increased strength and improved fatigue resistance. Raw material is sourced from premium suppliers in Europe with rigid specifications regarding chemical composition with low content of trace elements as well as low inclusion and slag content. All our products are delivered with full traceability and 3.1 certificate. Bumax 88 can also be delivered with a certificate that ensures that our fasteners fulfills the requirements according to the European Union’s pressure equipment directive (PED97/23) as well as with CE marking as structural bolt according to EN 15048. Our facilities are approved according ISO 9001, 14001 and ISO/TS 16949. Find our certificates in the link below:Downloads

CE Marking is a declaration by the manufacturer that the construction product has been made correctly and meets certain public safety requirements. The factory production control system and the essential characteristics for each product are described in a set of European standards called ‘harmonised’ standards. It will become mandatory for manufacturers to draw up a Declaration of Performance (DoP) and apply CE marking to any of their construction products which are covered by a harmonised European standard (hEN) or conforms to a European Technical Assessment (ETA).The individual requirements of fasteners in metallic constructions are regulated by the harmonized standards EN 15048 and EN 14399. Products which do not fall under a harmonized standard or a European technical approval (ETA) can still be distributed without CE marking. It is important to point out that DoP and CE marking is only required for construction products used in buildings when they will be permanently installed and at the same time have influence on the basic requirements for the building.Mechanical fasteners in A4 stainless steel are also affected by this directive. The harmonized standards that covers fasteners is EN 15048, fasteners for non-preloaded applications and EN 14399 for pre-loaded applications. However, 14399 does not apply to stainless steels.Bumax AB is certified by TUV Nord according to EN 15048 and BUMAX® 88 products can be supplied as a “structural bolt” with CE marking . The bolts will also be hard marked with “SB” according to the standard. However, CE marked structural bolts is not a standard product as it requires additional testing and marking compared to standard Bumax 88 . Upon inquiry / ordering of fasteners with usage that falls under the DoP and CE marking requirements it is important that this is clearly specified.Find our certificates in the link below:Downloads

Bumax Hard is a group of acid-proof,  self-tapping screws which can simply cut threads in stainless steel an carbon steel sheets. Bumax hard exhibits excellent Surface hardness and are made out of the same high quality material as Bumax 88. Bumax Hard is a great and cost efficient soultion for fitting sheet metal. Bumax Hard Taptite is a thread-forming screw which forms its own thread during assembly due to its trilobular shape, its conical entry thread and its excellent Surface hardness. Suitable for assembly in structural steel and cold rolled stainless steel with hardness up to 200HV.    Torque and strength for Bumax Hard Taptite ClassM3M4M5M6M8M10Tightening torque NmHard Taptite1.336122549Thread cutting torque NmHard Taptite0.71.83.581528Breaking torque, min NmHard Taptite4.57.913203052  Optimal hole diameters for Bumax Hard Taptite. Drilled or punched holes depending on material thickness and threadThread / Thickness⇒0.1-1.51.51-2.52.51-44.1-6.56.6-1010.1-15M3 2.7 2.8 2.8 2.85M4 3.65 3.65 3.7 3.75 3.8M5 4.6 4.7 4.7 4.75M6 5.5 5.6 5.6 5.655.7M8 7.5 7.5 7.6 7.7M10 9.3 9.3 9.4 9.5  Bumax Hard sheet metal screw (ST) is a self tapping screw with ST thread. Designed  for fitting to sheet metal and profiles of carrbon steel, as well as stainless steels. Optimal hole diameters and plate thickness (T) for Bumax Hard ST thread.TST2.9ST3.5ST4.2ST4.8ST5.5ST6.3<0.56 2.2 2.60.56-0.63 2.3 2.7 3.2 3.70.64-0.75 2.3 2.8 3.2 3.7 4.30.76-0.88 2.4 2.8 3.2 3.8 4.3 4.90.89-1.25 2.4 2.8 3.3 3.8 4.4 4.91.26-1.38 2.5 2.8 3.5 3.9 4.5 4.91.39-1.75 2.6 2.9 3.8 3.9 4.6 5.01.76-2.25 3.0 3.8 4.9 4.7 5.22.26-3.0 3.2 3.9 4.1 5.0 5.33.1-4.0 4.4 5.1 5.8