Downhole circular cutting torch

A method comprising:

• positioning a circular cutting torch in a casing or tubular desired to severed, the circular cutting torch including:
• a thermal igniter assembly, the thermal igniter assembly including a cartridge containment sub, a thermal igniter, and a thermal cartridge, the thermal cartridge including a cartridge housing and a nonexplosive combustible material positioned therein;
• a compressed grain magazine, the compressed grain magazine coupled to the thermal igniter, the compressed grain magazine including a magazine housing and a compressed nonexplosive combustible material positioned therein;
• and
• a severing head assembly coupled to the compressed grain magazine, the severing head assembly including a one-piece severing head and a progressive compression deflector, the one-piece severing head and progressive compression deflector defining a radial gap therebetween;
• activating the thermal igniter;
• igniting the nonexplosive combustible material of the thermal cartridge;
• igniting the compressed nonexplosive combustible material of the compressed grain magazine with exhaust gases and molten combustible material of the nonexplosive combustible material of the thermal cartridge;
• expelling exhaust gases and molten combustible material of the compressed nonexplosive combustible material of the compressed grain magazine through the radial gap of the severing head assembly;
• and
• cutting the casing or tubular using the exhaust gases and molten combustible material expelled through the radial gap.