As typically expected of super duplex stainless steel grades, Zeron 100 has an equal proportion of austenitic and ferritic microstructure. Referred to as a superalloy, the characteristics of Zeron 100 Fasteners are at par, if not better than the other super alloy grades. In particular, this super duplex stainless steel grade has terrific resistance to pitting. This is because of its higher PREN value.

Zeron 100 Fasteners

Zeron 100 Fasteners

A Pitting resistance equivalent number, or as shortened to PREN value is an indicator of how well an alloy will perform when exposed to pitting conditions. In this case, the Zeron 100 threaded rod was made to meet a PREN value of 40. A PREN value of more than 38 indicates that the alloy will have excellent resistance to pitting. This aside, the alloy used in the manufacture of Zeron 100 F55 nuts contains some content of copper. Per usual, an alloy which contains a part of copper has good resistance to sulfuric acid, as is the case of Zeron 100.


Another addition that makes the ASTM specified SA479 Zeron 100 Hex Bolts a better alloy than most others is nitrogen. Nitrogen is an element known to increase the austenite stability in stainless steel grades such as UNS S32760 fg stud bolts. Further nitrogen is also what increases the pitting resistance along with the yield strength of the alloy. In this instance, adding nitrogen is met with encouragement, as the yield strengths of Zeron 100 Screws is almost two times that of austentic stainless steel grades, particularly those belonging to the 300 series.

Zeron 100 Hex Bolt grade standard and specification

Sizing 3/6 inch upto 2 inch | M3 – M56
Specification ASTM / ASME F51 / F60 / F55
Lengths 3 upto 200 Millimetre
In Form of: Round, Threading, Hex, Square as per Gauge Etc.

Zeron 100 F55 nuts Chemical Compatibility Chart

Percentage Cr Ni Mo Cu W C N Mn Si P S Fe
Min 24 6 3 0.5 0.5 - 0.2 - - - - -
Max 26 8 4 1 1 0.03 0.3 1 1 0.030 0.010 Balance

Mechanical Properties of UNS S32760 fg stud bolts

Physical / Mechanical Property -70°C 300°C -46°C 21.1 °C 148.9 °C 93.3°C 204.4 °C 250 °C
Coefficient of Thermal Expansion /µm/m°C - 13.8 - - - 12.8 13.3 -
0.2% Yield Strength, MPa - 360 - 550 400 430 380 370
Ultimate Tensile Strength, MPa - 590 - 750 620 670 610 600
Reduction of area % - - - - - - - -
Charpy Impact V-notch /J >45 - >45 100 - - - -
Elongation % - - - 25 - - - -
Modulus of Elasticity / GPa - 180 - 200 - 194 186 -
Thermal Conductivity /kcal/(hr.m.°C) - 15.652 - 11.094 13.244 12.384 14.018 14.878

Zeron 100 Fasteners Equivalent grades

 Product European UNS ASTM/ASME
Super Duplex Zeron 100 1.4501 UNS S32760 F55/ F51/ F60

Zeron 100 Super duplex Screws Physical Characteristics

Density: 7.84 g/cm³
Melting Range: °C
Curie Temperature: °C
Specific Heat Capacity: 482 J/kg.°C
Hardness: 28 HRC max
Electrical Resistivity: 0.851 µΩ.m
Poisson's Ratio: 0.32