Abstract: A nozzle used in an abrasive blast cleaning apparatus through which a plurality of abrasive particles is propelled. The nozzle has a first bore with a constant first diameter, a radially converging section, a throat section with a constant second diameter, a radially diverging section, a second bore, and a second bore having a constant third diameter. The first bore defines a first end for receiving the abrasive particles and a second end. The radially converging section defines a third end connected to the second end and a fourth end. The throat section defines a fifth end and a sixth end, wherein the fifth end is connected to the fourth end of the converging section. The radially diverging section defines a seventh end and an eighth end, wherein the seventh end is connected to the sixth end of the throat section. The second bore defines a ninth end and an exit, wherein the ninth end is connected to the eighth end. The constant first and third diameters are larger than the constant second diameter.