A kind of corrosion phenomenon between the grains of stainless steel straps under the action of corrosive media is called intergranular corrosion. The stainless steel straps that produce intergranular corrosion will break along the grain boundaries when they are stressed. The strength is almost completely lost. This is one of the most dangerous forms of damage to stainless steel. Intergranular corrosion can occur in the heat-affected zone, weld or fusion line of welded joints. The intergranular corrosion on the fusion line is also called knife状 corrosion.

Stainless steel cable ties have corrosion resistance, and nylon cable ties also have corrosion resistance. The necessary condition is that the mass fraction of chromium must be greater than 12%. When the temperature rises, the diffusion rate of carbon in the grains of stainless steel cable ties is greater than that of chromium. The diffusion rate of carbon in the austenite at room temperature is very small, about 0.02% to 0.03%, and the carbon content of the austenitic stainless steel in general austenitic stainless steel sprayed with stainless steel exceeds this value, so it is redundant The carbon continuously diffuses to the austenite grain boundary and combines with chromium to form chromium carbide compounds, such as (CrFe)23C8, etc. between the crystals.

However, due to the low diffusion rate of chromium, it is too late to diffuse to the grain boundary. Therefore, the chromium required for the chromium carbide formed between the crystals is not mainly from the inside of the austenite grains, but from the vicinity of the grain boundaries. As a result, the grain boundaries The chromium content in the vicinity is greatly reduced. When the mass fraction of chromium at the grain boundary is as low as less than 12%, a so-called “chromium-depleted zone” is formed. Under the action of corrosive media, the chromium-depleted zone will lose its corrosion resistance. And produce intergranular corrosion.

Intergranular corrosion of stainless steel cable ties, unstable austenitic stainless steel with a carbon content of more than 0.03% (no titanium or niobium grades), stainless steel sprayed cable ties may easily produce crystals in some environments if they are improperly treated. Intergranular corrosion. When these steels are heated between 425-815°C or slowly cooled through this temperature range, intergranular corrosion will occur. Such heat treatment causes carbides to precipitate at the grain boundaries (sensitization) and cause the nearest neighbors Depletion of chromium in the areas makes these areas susceptible to corrosion.

The most common method for checking the sensitivity of stainless steel cable ties is the 65% nitric acid corrosion test method. During the test, the steel sample is placed in a boiling 65% nitric acid solution for a continuous 48h cycle, a total of 5 cycles, and the weight is measured in each cycle For loss, it is generally stipulated that the average corrosion rate of 5 test cycles should not be greater than 0.05mm/month.

In the market, we can see that the materials of cable ties are generally stainless steel and nylon. Compared with nylon cable ties, stainless steel spray cable ties and stainless steel cable ties are more popular with users. So why is that?

Although nylon cable ties are small in size, light in weight, and beautiful in appearance, they are not strong enough. In terms of durability, stainless steel cable ties have outstanding advantages. They have strong cutting force, fast tightening speed, small size and easy to carry.

Compared with ordinary nylon cable ties, stainless steel cable ties use a special customized fixing rod, which can seal both ends of the fixing, so that the accessories will not fall apart and fall apart.

Compared with nylon ties, stainless steel cable ties have a longer service life. Better stainless steel materials can meet long-term outdoor use conditions and have good oxidation resistance and acid and alkali corrosion resistance in harsh environments.

In addition, stainless steel cable ties have a wide range of uses, industry, agriculture, communications, transportation, etc. can see its use.