316L/1.4435/SEMI F20 UHP

Quick Facts

This Alloy is a modified 316L version an austenitic stainless steel, a low carbon version of 316 and normally melted as AOD, AOD + VAR, or VIM + VAR or ESR + VAR. The low carbon helps to improve weldability as compared to the standard 316 as well as improved corrosion resistance! This version is called UHP (ultra-high purity). It can be used for manufacturing of components for general purpose and high purity chemical (gas or liquid) distribution systems in semiconductor manufacturing facilities.

Typical Applications

  • General Clean Room Fittings
  • Valves
  • UHP pressure Sensors
  • Metal UHP sealings
  • Welding fittings

Stock Range

We stock a comprehensive range of Flat Bars and Round Bars.
Flat Bars with a thickness between 12.70mm (0.5”) – 44.45mm (1.75”) and various width, we are cutting to size.
Round Bars from OD 6.36mm (0.25”) to 76.20mm (3”).
Seamless Tubes, only on indent and customers demand and specifications!

We are offering as well:
General forgings
Primarily manufactured in Europe,

Relevent Specifications

  • SEMI F20-UHP
  • AISI or SUS 316L
  • EN 10277 class 3, surface
  • EN 10308
  • ASTM A 276-Rev.2016, ASTM A 479/A, 479M Rev. 2016
  • ASTM E112 Rev. 2013, ASTM E45 Rev. 2013, ASTM A262 practice E Rev. 2015

Material may also be supplied against Customer specifications, subject to enquiry!

Melting Practices

  • Our material is either double or triple melted and complies with double V melting practice and quality,
  • acc. to ASTM A 276 / EN 10 088-3,

Chemical Analysis

This Alloy is a modified 316L version an austenitic stainless steel

Chemical Composition, %

316L/1.4435/SEMI F20 UHP

Mechanical Properties

OD 6.35mm up to 25.40mm h9 tolerance
OD 26.00mm and above k12 tolerance,
Straightness 2.00 mm/m
Surface depth acc. to EN 10277, class 3
Grain Size acc. to ASTM E112 ≤ 5
General standard EN 10088-3, ASTM A 276

Please take note Grain Size shall be defined by customer. Below Grain size shows AMS internal standards
and may be changed!

316L/1.4435/SEMI F20 UHP


Type A-UHP (ultra-high purity)

316L/1.4435/SEMI F20 UHP

Type B-HP (high purity)

316L/1.4435/SEMI F20 UHP

Material Conditions, general

SEMI F20 defines the metallurgical cleanliness requirements and material composition of 316L stainless steel for use in manufacturing of components for general purpose, high purity, and ultra-high purity chemical (gas or liquid) distribution systems.
It defines the requirements for 316L stainless steel bar, forgings, and extruded shapes as specified in ASTM A 276, plate stock as specified in ASTM A 240, and tubing as specified in ASTM A 269 and ASTM A 632, for use in the manufacture of components used in general purpose and high purity chemical (gas or liquid) distribution systems in semiconductor manufacturing facilities.
As far as we know the first SEMI F20 was published in 1995. From the history we know that manufactures are capable to achieve the purity last time by using VIM and VAR melting processes.
Since in the past mostly American manufacturers are supplied such grades, the industry got used to it, using VIM/ VAR material.
As a result, everybody was using VIM/VAR material even though it was not defined as a method or process to achieve the purity.
However, during the last decades technologies developed other processes achieving same or better results in purity. AMS can guarantee, that we are capable of supplying SEMI F20 316L UHP material in full compliance with the current relevant standards.

Corrosion Resistance

316L-SEMI F20-UHP has an excellent corrosion resistance. The low carbon content effectively reduces the susceptibility to intergranular corrosion. The presence of molybdenum enhances the resistance to oxidizing acids as well as to pitting corrosion.