Sherardize

The Standards For Use In Sherardized Coatings

BS EN 13811:2003

Sherardizing - Zinc diffusion coatings on ferrous products.
The European Standard above has the status of a British Standard and is replacing BS4921.

CLASS OF COATING LOCAL COATING THICKNESS
(MINIMUM VALUE)
CLASS 15 15 µm
CLASS 30 30 µm
CLASS 45 45 µm
TABLE 1.BS EN 13811:2003 COATING MINIMUM THICKNESS IN MICRONS

BS 4921

Sherardized coatings on iron and steel articles.

CLASS OF COATING LOCAL COATING THICKNESS
(MINIMUM VALUE)
CLASS 1 30 µm
CLASS 2 15 µm
TABLE 2. BS 4921 COATING MINIMUM THICKNESS IN MICRONS

BS 7371-8:1998

Coatings on Metal Fasteners

CLASS OF COATING LOCAL COATING
THICKNESS
(MINIMUM AVERAGE
VALUE) 		ADDITIONAL THREAD
CLEARANCE for ISO
METRIC COURSE THREADS
S1 30 MICRONS 360 µm
S2 15 MICRONS 180 µm
S3 30 MICRONS PLUS SEALANT 360 µm
TABLE 1.BS EN 13811:2003 COATING MINIMUM THICKNESS IN MICRONS

DEF Stan 21-005/Issue 2

Ministry of Defence Code of practice for protective finishes

ADDITIONAL USEFUL STANDARDS

ISO 9223:1992

Atmospheric Corrosivity - Corrosion of Metals and Alloys

ASTM B117

Salt Spray Testing.

BS EN ISO 9227:2006

Corrosion Tests in artificial atmospheres - Salt Spray Tests.

Technical Specifications And Standards

Introduction

Corrosion control begins at the design stage and requires the awareness and co-operation of the entire engineering design team.

In order to ensure the correct specification, the many factors influencing corrosion, including environment, stress, shape and desired design life must be taken in to account

The service life of any zinc coating in a given environment is proportional to the thickness of the coating itself and is an important consideration when specifying.

When specifying Sherardized components, it is vital to consider the factors specific to the process itself.

  • Components should be able to withstand process temperatures of 380-500 ˚C
  • Components must fit into process containers, maximum [2000x500x400mm]
  • Threaded components must have allowances for thread clearance.
  • Components should not have any airtight voids as distortion may occour 
  • Salt Spray Test requirements, standard Sherardizing 96 hours, Sherardize P1000® in excess of 1000 hours to ASTM B117.

Our technical team are on hand to provide assistance if required, and samples are available upon request.