Steel Structure Design - Engineering

Q1:

For a steel member of slenderness ratio 350, the allowable stress is 76 kg/cm2 if it is

A HTW grade of thickness exceeding 32 mm

B HT grade of thickness exceeding 45 mm

C HT grade of thickness not exceeding 45 mm

D All the above.

ANS:D - All the above.

HTW stands for?