The effective cost dust content of molding sand should be determined according to time factors such as the quality of the coal dust, casting size and thickness, pouring temperature, lacing sand or unit sand, and so on.

• 决定型砂中的有效煤粉含量应根据煤粉质量的优劣、铸件大小和厚薄，浇注温度、面砂或单一砂等因素。