Question: the operation of joining two or more parts together by molten metal is called
[{'answer': 'Welding', 'provenance': [{'wikipedia_id': '266443', 'title': 'Metalworking', 'start_paragraph_id': 116, 'start_character': 11, 'end_paragraph_id': 116, 'end_character': 18, 'bleu_score': 1.0, 'section': 'Section::::Joining processes.\n'}]}, {'provenance': [{'wikipedia_id': '266443', 'title': 'Metalworking', 'start_paragraph_id': 117, 'start_character': 0, 'end_paragraph_id': 117, 'end_character': 350, 'bleu_score': 0.9657992495762461, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12688919607476025987}, 'section': 'Section::::Joining processes.:Welding.\n'}]}]