We have delivered fasteners with a strength exceeding class 15.9 for applications where down sizing, clamping force and strength are critical. In our product range we offer stainless fasteners ranging from strength class 8.8 to 16.9. Despite the high strength our unique materials offers a unique combination of ultra high strength and good ductility. Bumax Stainless steel fastners are resistant against hydrogen embrittlement.


High strength fasteners offers:

  • possibility to downsize the fastener  or reduce the amount of fasteners with maintained clamp load
  • weight saving
  • compact design and smaller screw joints
  • a fasteners that are able to withstand higher static or dynamic stresses
  • higher safety factor
  • higher resistance against relaxation



Mechanical properties

in as delivered condition for screws and bolts

Grade DimensionStrength classTensile strength Rm, min (MPa)Yield strength Rp0.2, min (MPa)Elongation, min (mm)
BUMAX 88M3-M36888006400.3 d
BUMAX 109M3-M2010910009000.2 d
BUMAX Nitro up to M42109, 1291000, 1200900, 10800.2 d
BUMAX SA up to M4288, 109800, 1000640, 9000.2 d
BUMAX LDX up to M4288, 109, 129800, 1000, 1200640, 900, 10800.3 d
BUMAX DX up to M4288, 109, 129800, 1000, 1200640, 900, 10800.3 d
BUMAX SDX up to M4288, 109, 129800, 1000, 1200640, 900, 10800.3 d
BUMAX HDX up to M888, 109, 129800, 1000, 1200640, 900, 10800.3 d
BUMAX Ultra¹ up to M16159, 1691500, 16001350, 14400.2 d

The table should be used as a guide only of what is possible to achive in regards of mechanical properties and dimension for Bumax grades. Alteration might occur depending on design and dimension. Contact Bumax sales representative for more information.


1) Bumax Ultra is a grade that is tailor made to solve customer needs in regards of strength, ductility, fatigue and wear resistance. Values in the table are typical strength classes, but even higher strength can be achived on some designs and dimensions, up to tensile strength levels of approximatly 2500 MPa.