ASTM B117 Operating Salt Spray (Fog) Apparatus

ASTM B117 Introduction

ASTM B117 test method is designed to cover the requirements for establishing and maintaining a salt spray test environment. This method provides relative corrosion resistance information related to a controlled corrosion environment for metal specimens and coated metals. The results obtained are specially used for quality control and specification purposes.

The B117 test method is generally applicable to metals and provides information about the performance, variability among the specimens, correlation, and extrapolation of corrosion. Variability is observed by testing similar specimens in different fog chambers under specified ranges. MaTestLab is one of the leading testing service providers in the USA and Canada for metals and alloys testing. We have a large network of testing laboratories in the USA.

Salt Spray Corrosion Testing

Get Certified for ASTM B117 for Reliable Corrosion Testing

Compliance assists in coating validation, quality-assurance programmes, and supplier validation, as well as regulatory inspection. Manufacturers and coating applicators use ASTM B117-certified tests to check the durability of the coating, evaluate corrosion-inhibiting treatment, and filter out materials before being subjected to the field. Certification enhances customer confidence since material performance assertions are backed by reliable, verifiable, and international testing.

ASTM B117 Testing Procedure and Requirements

Scope of ASTM B117

• ASTM B117 offers a common method of operation of salt spray testing of coated and uncoated metallic materials. 
• It is used with paints and organic coatings, electroplated coatings, galvanic coatings, anodic coatings, conversion coatings, metal finishes, stainless steel, aluminium alloys, and corrosion-inhibitory surface treatments.
• The standard provides recommendations on equipment needs, how the solutions should be prepared, environmental factors, monitoring, positioning of the specimens, and documentation. 
• ASTM B117 lacks a pass-fail; the specifications of requirements are provided in the specifications of materials or products.

ASTM B117 Equipment and Sample Preparation

Use of ASTM B117

• Measures the resistance of metals and coated materials to corrosion in controlled conditions of salt mist.
• Comparing the performance of protective coatings like paints, platings, and galvanizing.
• Enhances quality monitoring through the detection of defects in the coating, such as pores, cracks, or poor bonding.
• Helps in the product development departments to enhance corrosion protection mechanisms.
• Helps manufacturers comply with regulatory and customer requirements on corrosion durability.
• Offers enhanced corrosion information in real-time research, material choice, and warranties.

Common Challenges and Troubleshooting

The concerns of troubleshooting revolve around checking the chamber calibration, cleaning the atomising nozzles, proper solution concentration, temperature stability, clean water supply, and positioning of the specimen. An untidy pre-test cleaning can cause wrong corrosion patterns, and corrosion chambers can leak, which changes the density of the fog.

ASTM B117 Testing Technique, Process, and Data Collection

Testing is carried out under an atmosphere of continuously exposed salt mist on specimens. The operators enter measures of temperature, fallout rate, solution pH, and chamber conditions at regular intervals. Others, such as the data on the distribution of mogs, visual check records, solution make-up logs, and environmental stability. On completion, the documentation of corrosion products is done according to rust grade, size of a blister, loss of coating adhesion, scribe creep, pitting, delamination, or discolouration, depending on the class of the material and specification.

Analysis, Results, and Interpretation

Findings are qualitative and interpretative and aim at the study of corrosion behaviour in challenging conditions. A coating that can exhibit a lower degree of blistering or rust upon prolonged exposure to the fog is reckoned to be stronger. Excessive rusting or coating corrosion in an area denotes a lack of corrosion protection. Interpretation should take into account the type of material, coating chemistry, preparation of the specimen, and exposure period.

Problem & Solution for ASTM B117

Problem: Inconsistent fog distribution, poor chamber sealing, incorrect salt concentration, pH deviation, or unexpected corrosion patterns.
Solution: Calibration of the system, cleaning, checking the concentration and pH of the solution used, checking the stable chamber, and handling of the specimen. Repeatability might require the repetition of tests.

Factors to Consider for ASTM B117

Speed: The test provides rapid corrosion screening, though exposure periods may extend from hours to thousands of hours depending on material requirements.
Expert: Skilled personnel are required to maintain a consistent fog environment and interpret corrosion patterns.
Cost: The cost of the test includes the chamber, salt solution preparation, monitoring equipment and labor; nevertheless, the test is affordable in the detection of a coating failure at its early stage.