چکیده:
The aim of this study is to study effect of particular heat treatment on performance of 304 Stainless steel alloy which is one of the most applicable grades of austenitic stainless steel used widely in storage tank to chemical transportation. Although this alloy has suitable properties for engineering uses, its poor resistance to intergranular corrosion restricted its use in industries. Meanwhile, this problem lead to reduction in the average working hours in equipment in which 304 alloy is used. To remedy this problem, there are many different methods has been introduced in the recent decades. However, finding a method which increase corrosion resistance of alloy without any collapse in other alloy’s properties still a challenge. In this study, different heat treatment cycles on the 304 alloy were applied and then the corrosion rate was measured. Furthermore, mechanical tests were carried out to find out which cycle resulted in optimum properties. The results illustrated that reducing carbide participate led to better mechanical properties as well as corrosion resistance.
خلاصه ماشینی:
Effect of Solution Annealing Heat Treatment on the Corrosion Resistance and Mechanical Properties of an Austenitic Stainless Steel Ali Alavi Shoushtari*1, Meysam Sharafi 1, Sina Sekhavat2 1 IKA Enginereening and Technical Inspection Copmany, Tehran, Iran 2Absun Zolal Engneering Company, Tehran, Iran *Corresponding author’s E-mail:Alialavi.
There are many tests and experiments to determine types of corrosion in austenitic stainless steels, but the measurement of intergranular corrosion by using standard chemical solutions according to ASTM A262 is the most famous and acceptable one [11].
In this paper, the effect of solution annealing heat treatment on the corrosion rate and mechanical properties of 304 stainless steels was studied to attain the optimum temperature and holding time.
So, the type B and C test from the mentioned standard could be done: A) Results from method B (Iron Sulphate – boiling sulphuric acid solution): the corrosion rate of 15 specimens in millimeter per month was calculated.
Figure 2 shows the variation of corrosion rate on time of solution annealing heat treatment.
The noticeable point in the calculation according to method B of ASTM A262 was that after a specific annealing time, holding in 1100oC did not have any particular effect on the corrosion rate and just caused energy loss and a collapse in mechanical properties due to increase in grain size.
Conclusion According to test results, stainless steel grade 304 corrosion properties improved by solution annealing heat treatment, but this improvement stopped after specific time.