The present article covers the research on the influence of a heat flow reflection from the edge, which provokes addition heating at the end of a joint and as a result changes its quality (structure and mechanical characteristics), weld seam geometry. It's demonstrated that under single electrode arc welding the heat reflection influences greatly the geometry of a welding seam, boosts enlargement of a grain in thermal impact zone and lowers impact strength. Due to this fact it's necessary to regulate the heat input at the end of a joint. Under double-electrode arc welding we can witness little if any influence of a heat flow reflection, which proves that it's worth to use this method to lower the influence of a reflected heat flow.