Corrosion Coupon Strip Metal Sample

Description

EMT-CI Corrosion Coupon is used to monitor the corrosion rates of the sample (coupon) in the pipe or container. By observing the mils-per-year corrosion rate of an exposed coupon, valuable information can be provided regarding the material’s life expectancy. So if you want to know more about Corrosion Coupon, please contact our professionals to answer them for you.

1. What is the coupon corrosion test?

The coupon corrosion test is carried out under the given conditions in the laboratory. We calculate the corrosion rate and corrosion inhibition rate by the mass loss of the test piece. Then it works to evaluate the corrosion inhibition performance of water treatment agents. Through the coupon test, the huge economic loss caused by corrosion hazards can be reduced. Improve the safety of people, industrial production equipment, and important infrastructure. Coupon corrosion test has important application value in the chemical cleaning of industrial equipment.

The most commonly used measurement method for corrosion tests is the gravimetric method. It includes the weight gain method and weight loss method. We firmly attach corrosion products to the specimen. And it is also almost insoluble in solution. At this time, we can determine the degree of corrosion damage by the weight gain method. The weight gain method is applicable to evaluate the total corrosion and intergranular corrosion. But it is not suitable for other types of local corrosion. Weightlessness is a simple and direct method. It does not require corrosion products to adhere firmly to the material surface.

At the same time, it does not consider the solubility of corrosion products. The weight loss method directly represents the weight of material lost due to corrosion. It does not need to undergo chemical composition analysis and conversion of corrosion products. The measurement method of the coupon corrosion test is usually the weight loss method in the gravimetric method to calculate the corrosion rate and the corrosion mass

2. Summary of key points of coupon corrosion test

(1) GB / t25147-2010 corrosion rate of metals in chemical cleaning of industrial equipment. There is also a test method for the total amount of corrosion (gravimetric method)
Scope of application: This standard specifies the metal corrosion rate in the chemical cleaning of industrial equipment. There is also a test method for the total amount of corrosion. This is applicable to the metal corrosion rate in the laboratory and cleaning site before the chemical cleaning of industrial equipment. And the determination of total corrosion.

Summary of the test method: immerse the prepared and accurately weighed metal test pieces in the test solution. After completing the test. We take out the test piece and weigh it after treatment. Then the mass loss of the test piece calculates the corrosion rate and total corrosion amount of the test solution to the metal of the test piece. To evaluate the corrosion rate and total corrosion amount of industrial equipment in the process of chemical cleaning.

Test form:

laboratory coupon test and field coupon test

Sample requirements:

The material of the test piece is consistent with the metal material actually cleaned. The specification, shape and dimension, processing procedure, and appearance of the test piece shall meet the requirements of Hg / T 3523. The test piece shall be degreased and cleaned before the test. No less than 3 test pieces of the same material.

Test solution:

Use distilled water and analytical pure reagent to prepare a test solution equivalent to the cleaning solution determined by the cleaning scheme. The volume of the test solution is generally required to be no less than 20ml per 1cm of the surface area of the test piece. Not more than 40ml
(2) GB / t19291-2003 corrosion of metals and alloys – General principles of corrosion testing

Scope of application:

So this standard specifies the most important general principles for corrosion tests under certain immersion conditions

General principles:

1. Firstly, corrosion tests are usually tests for comparison. That is, a group of materials or corrosive media are compared under given test conditions. However, it is also possible to include a base material or a reference solution whose damage is known under actual conditions. Have an objective and clear understanding of the purpose of any corrosion test procedure. It is also important to select the most appropriate method to evaluate the corrosion damage.
2. Secondly, During the test. The degree of damage was observed as a function of time. And make quantitative records as much as possible. The purpose of most types of tests shall be to determine the condition of the specimen in at least three different cases except the initial state of the test. Extend the time beyond the original plan.
3. Whenever possible, at least three tests shall be carried out at each measuring point. And then check the test results.
4. The test conditions shall be as equivalent as possible to the conditions of materials and corrosive media in actual use.
5. At last, when applying accelerated corrosion test results.

Material requirements:

The details of the condition of the test specimen must be also clearly understood. Such as chemical composition, state and processing details, and material form. It also includes the sampling position, size, quality, and surface condition. There are also mechanical properties, structure, protective layer, and coating.

Corrosive medium:

We must clearly describe the corrosive medium. In particular, the source, composition, preparation method and the state of the corrosion medium provided

Evaluation of test results:

Evaluation method of corrosion damage and corrosion rate of samples