B. Ti micro-alloyed steels have a degree of tempered martensite structure in projectile proof armour steel plate. To make very thin sheets 1.73 to 5.0 mm thick and still retain the property to withstand hits of high velocity bullets upto 900 m/s require specific use of NDE at every stage of manufacturing starting from ingot stage which are examined by ultrasonic testing (UT) to the rolled sheet which are checked by radiography (RT) and fluorescent magnetic particle inspection (FMPI). After further processing when they have undergone heavy reduction and the surface has to bear the maximum stress and strain, they are examined by UT to ascertain that the microstructure has not obliterated and FMPI using magnetic leakage flux technique for minute surface cracks. The finished sheets are 100 percent hardness tested to ensure toughness. Finally destructive testing is carried out on 10 percent of finished product to prove their reliability in actual service conditions statistical analysis of the test data for UT, RT, FMPI and hardness is carried out to see that the quality is maintained.

The thin sheets are used for making bullet proof jackets and shields armour bullet proof helmets for defence personnel. The statistical analysis also gives an indication where to reduce weight without compromising other properties, since weight is the most important factor for free movement.

The details of the salient features in the production of special shapes of the helmet and NDE evaluation with illustrations of microstructure and testing are given and discussed in the text of the paper.