Corrosion cracking and fracture of stainless steel
You are interested in stress corrosion cracking and fracture of weld to stainless steels, from the company — supplier Alekhlas? Here you will find the necessary information on the topic.
Definition
The combination of tensile stress and a specific corrosive environment can locally destroy stainless steel by cracking. This mode of attack is called corrosion stress cracking. The most common condition effects on the environment that causes stress corrosion cracking of stainless steels, is the presence of chlorides.
Despite the fact that none of the grades of stainless steel is not immune to chlorides, the relative resistance of stainless steels varies considerably.
The influence of steel composition
The relative resistance to chloride depends on the type of stainless steel. The most susceptible to this phenomenon austenitic steel. The resistance of austenitic stainless steels stress corrosion cracking is associated with the Nickel content in the steel. The most susceptible austenitic grades have Nickel content in the range of 8 to 10%. Austenitic grades with a relatively high content of Nickel and molybdenum have significantly better resistance to chlorides.
Stainless steels of the ferritic class have increased resistance to chlorides. Duplex stainless steel with dual austenitic / ferritic microstructures has a resistance that is between the steels of the austenitic and ferritic grades.
Supplier — the company Alekhlas — offers to purchase assortimente metal, made of different grades of stainless steels. Products can be purchased at a price formed on the basis of European and world standards. Possible, wholesale and retail, for regular customers a flexible system of discounts.
Assessment of stress corrosion cracking
The relative resistance of stainless steel to chlorides are determined quantitatively using a standard boiling salt solutions of sodium chloride, lithium chloride and magnesium chloride. Test solutions for boiling based on the LiCl and MgCl2 are very aggressive compared to practical applications, and is suitable only for testing of stainless austenitic steels.
Prevention of rastreskivanija
A typical crack morphology for chloride stress corrosion cracking consists of cracks branched transgranular. Environmental factors that increase susceptibility to corrosion cracking include higher temperatures, increased chloride content, lower pH and higher levels of tensile stresses.
An important variable is temperature. Stress corrosion cracking under the action of the chlorides is rarely observed at temperatures below 60 ° C.
There is a relationship between dissolved oxygen and level of chlorides. If the oxygen level is reduced to 0.01 to 0.1 ppm, aqueous solutions containing levels of chloride with a low to moderate level, almost do not destroy the austenitic steel. In real conditions the evaporation can produce local emission of aggressive substances such as chlorides and H + ions, which leads to much more aggressive conditions. In the harsh conditions of evaporation, stainless steels can crack at temperatures significantly below the thresholds. Therefore, care should be taken when assigning materials for applications associated with evaporation of chloride solutions on hot surfaces of stainless steel.
Supplier — the company Avecho offers various types of stainless steel domestic and foreign production. Products are offered at affordable prices from the manufacturer. Supplier guaranteed timely delivery at any address specified by the consumer.