IR is Only For Industrial Related. HR is For Over All Human Resources About Management. Both are Differed Like Differed in Job Description Wise.
IR is related to Industrial Relations, meaning trade unions, strikes, grievances, and involvement of political parties. If you search on any search engine, you will find a lot of material to read on this topic. Generically speaking, IR is applicable to companies with manufacturing units or factories. It involves taking care of employee issues of factory workers and maintaining a good relationship with trade union leaders to prevent strikes.
HR is more about human resource management, involving activities such as recruitment, HR planning, training, organizational development, and performance management. IR is a part of HR. Hope this explanation helps.
HR Field is a good field. To compare, IR is an important aspect to consider.