Mohammad Nawaz was put into the attack to bowl his first over, with Steemkamp taking a single off his second delivery after a dot ball.
Nawaz conceded another run on the next ball with a wide down the leg side before Erasmus passed the strike to Steemkamp for another single.
After a dot ball, Nawaz successfully dismissed Steenkamp with Usman Khan taking an easy catch.
New man in was Volschenk who took the strike and ended the over with a dot ball.
Namibia are 43-3 after seven overs.
