What is the difference between SS316 and SS316L

The difference between SS316 and SS316L is that of suffix 'L'. This L stands for low carbon.

                            Chemical composition of SS316 and SS316L

                       Cmax    P       S         Si      Mn     Cr        Ni      Mo

     SS316       0.08   0.045   0.03   0.75   2.0   16-18   10-14   2-3
     SS316L     0.03   0.045   0.03   0.75   2.0   16-18   10-14   2-3

From the above table we can see that SS316L has a 0.03% max carbon where as SS316 has a 0.08% max carbon. The low carbon in SS316L improves its wediability at high temperature. In a corrosive environment,SS316L used to minimize intergranulor corrosion.

What is the difference between SS304 and SS316

                          

Both SS304 and SS316 are austenitic stainless steels.

         CHEMICAL COMPOSITION OF SS304 AND SS316               

              C       Mn       P         S        Si           Cr              Ni             Mo

        

SS304  0.08    2.0    0.045   0.03    1.0    18.0-20.0     8.0-10.0        -

SS316  0.08    2.0    0.045   0.03    1.0    16.0-18.0    10.0-14.0    2.0-3.0 

 From the above chemical composition chart we can see the main difference between SS304 and SS316 is that SS316 contains 2%-3% molybdenum and SS304 has no molybdenum.Now the question arises that we are paying double money for SS316 only for that 2.5% 'Moly'.The answer is yes, because this  "molybdenum" is added to improve the corrosion resistance to chlorides (like sea water).That is why in coastal area plants SS316 is used.

Why addition of molybdenum improves resistance against chloride corrosion?

Role of Mechanical Maintenance Engineer

The role of a mechanical maintenance engineer has become very important aspect in production industries(eg.fertilizer industry, chemical industry, petroleum industry,cement industry etc).It can be understood with a very simple equation,

Failure of machine is directly proportional to production loss

And here comes the challenging role of maintenance engineer to prevent break down of machines.

Whenever we are sick, we consult doctor to get cured. Doctor examines us and if required refer for pathologycal tests,finally based on all the reports medicines are given.

Similarly a mechanical maintenance engineer is the DOCTOR of MACHINE. Maintenance engineer looks,listens and feels the machine to under the reason of machines sickness(i.e. high vibration,abnormal noise, high temperature etc ).

To give correct diagnosys vast knowledge of material science, vibration analysis,bearings,corrosion protection, rotodynamics, paint technology, rotory machines eg pumps, turbines, bucket elevators etc is required.

In this blog we will discuss our day to day maintenance problems and their troubleshooting.