Selection of factors to be considered stainless steel
Corrosive environment in the choice of stainless steel, except stainless steel to deal with the specific conditions of use detailed knowledge, but also a major factor to be considered are: stainless steel corrosion resistance, strength, toughness and the physical properties, processing, forming properties, resources, price and the ease of access. Including corrosion resistance of stainless steel corrosion resistance and acid, alkali, salt and other corrosive media performance and high temperature anti-oxidation, sulfide, chloride, fluoride, such as performance.
Stainless steel as a result of the alternative is to solve practical engineering in a variety of corrosion problems encountered in this environment in the corrosion of the corrosion resistance of stainless steel is the material on how staff in the first place needs to be considered. Corrosion between the metal and dielectric function due to chemical or electrochemical damage caused, and the corrosion resistance of stainless steel to resist media refers to the ability of corrosion damage, so when the material involved in corrosion resistance, the need to pay attention to the following points.
1. Corrosion resistance of the standard is determined by man-made, it is necessary to recognize it, use it, can not be bound by it, according to the specific requirements to determine whether the use of specific standards for corrosion resistance. At present, the corrosion resistance of stainless steel used 10 criteria to choose which level the requirements for corrosion resistance, it is necessary to consider the equipment, the characteristics (thickness, size).
The length of life, product quality (such as impurities, color, purity), etc., generally speaking, the course requirements on the use of mirror-smooth or size of sophisticated instrumentation and equipment parts, can choose 1 to 3 standards; to require close with long-term or require the use of limited leakage of equipment, parts 2 to 5 election, and do not ask for much maintenance does not facilitate or require a very long life of equipment, components can use 4 to 7, with the exception of the special exception, stainless steel in use under the conditions of corrosion rate of more than 1mm in generally do not choose, be noted that the standard 10 hours to produce localized corrosion is not applicable.
2. Corrosion resistance is relative, conditional, it is often said of the stainless steel, and corrosion resistance compared with the line pointing rust and corrosion resistance, it is referring to under certain conditions (medium, concentration, temperature, impurities, pressure, flow rate, such as certain hours).
So far, there is no corrosion in any environment are stainless, and corrosion resistance of stainless steel, wood staff, therefore the heart must be options for them to choose the specific conditions of use, stainless steel grade selected, the user departments also chosen for The proper use of the characteristics of stainless steel, that is a reasonable increase in the proper use of materials to achieve with a stainless steel or corrosion-resistant purposes.
So far, there is no corrosion in any environment are stainless, and corrosion resistance of stainless steel, wood staff, therefore the heart must be options for them to choose the specific conditions of use, stainless steel grade selected, the user departments also chosen for The proper use of the characteristics of stainless steel, that is a reasonable increase in the proper use of materials to achieve with a stainless steel or corrosion-resistant purposes.
3. Choice of stainless steel it is necessary to consider the general corrosion resistance performance, but also consider the performance of localized corrosion resistance in some media and chemical water medium, the latter need to be aware that this is because, generally more attention to selection of resistant stainless steel general corrosion, and in the use of conditions, their localized corrosion, such as pitting corrosion on the stress sensitivity, such as how to consider less; the localized corrosion of stainless steel and more resistant to general corrosion in a very good corrosion occurred in the environment, local often lead to corrosion of stainless steel equipment, parts of a sudden destruction, far greater than its harmfulness of corrosion in general.
4. In the manual application of the corrosion resistance of the stainless steel data, many of them to the attention of a number of experimental data is only the test results, the environment and the actual media often have a greater access to, in order to get closer to the actual conditions of use of the corrosion resistance data should in general be carried out in the laboratory corrosion test of the actual media or at the scene of the hanging under the conditions of test, if necessary, but also to simulate the test device. Used in a number of conditions, will encounter this situation, when the work or the production medium of industrial products, even with one or a small amount of the metal ions in stainless steel, it will affect the chemical industry process workers the quality of the product (including gloss, color, purity, etc.).
This situation of nuclear fuel, such as pharmaceutical and paint industries are most common at this time often does not contain some element of choice of stainless steel or stainless steel to increase corrosion resistance of the selected level in order to reduce metal ions to the limits allowed. 5. Stainless steel equipment, parts failure due to corrosion, it should be carried out analysis of the causes of corrosion damage, to take measures to identify the causes, rather than fling is over.