Can the limitations for free checked luggage exceed 44 pounds for two people?

I will be traveling with a senior and plan to only bring one piece of luggage for both of us. Can the limitations for this one piece of luggage for two people exceed 44 pounds (20 kgs) without getting charge for the extra weight? For example, will China's domestic airline allow two people traveling together to bring on a free checked luggage that is 55 pounds for economy class?