The selection of lapping tool material shall be determined by the material and performance of valve grinding parts. The lapping tool material shall have the characteristics of fine and uniform structure, good sand embedding performance, good wear resistance, sufficient stiffness, no deformation, and its hardness is softer than that of the abrasive part.

選擇研具材料應由閥門研磨件的材質及性能而定。研具材料應具有：組織細密均勻，嵌沙性能好，有良好的耐磨性，足夠的剛度，不變形，其硬度比研磨件要軟的特性。

The selection of lapping tool material shall be determined by the material and performance of valve grinding parts. The lapping tool material shall have the characteristics of fine and uniform structure, good sand embedding performance, good wear resistance, sufficient stiffness, no deformation, and its hardness is softer than that of the abrasive part.

通常用于做研具的材料有如下幾種。

There are several materials commonly used as lapping tools.

鑄鐵：鑄鐵含有片狀石墨，其耐磨性和潤滑性好，強度也高，它還具有成本低，易加工等優點。因此，鑄鐵研具適于研磨像硬質合金、淬硬鋼、有色金屬等多種材料的工件，也適用于敷砂研磨、嵌砂研磨和夾砂布研磨。鑄鐵具使用的材料有灰口鑄鐵和球墨鑄鐵，一般硬度為HB120～220。鑄鐵研具能確保質量，同時研磨的效率高，使用普遍。

Cast iron: cast iron contains flake graphite, which has good wear resistance, lubricity and high strength. It also has the advantages of low cost and easy processing. Therefore, cast iron grinding tools are suitable for grinding workpieces of various materials such as cemented carbide, hardened steel and non-ferrous metals. They are also suitable for sand coating grinding, sand embedding grinding and abrasive cloth grinding. The materials used for cast iron tools include gray cast iron and nodular cast iron, with a general hardness of hb120 ~ 220. Cast iron grinding tool can ensure the quality, at the same time, the grinding efficiency is high, and it is widely used.

低碳鋼：低碳鋼的韌性比鑄鐵大，能適應鑄鐵難得研磨的細長圓孔、圓錐孔、螺紋等工件，低碳鋼一般作粗研材料。

Low carbon steel: the toughness of low carbon steel is greater than that of cast iron. It can adapt to slender round holes, conical holes, threads and other workpieces rarely ground by cast iron. Low carbon steel is generally used as rough grinding material.

銅：銅韌性大，耐磨性好，適于加工余量大粗糙度要求低的工作的粗研閥門，能起低碳鋼研具的作用（但成本高，一般極少采用）。

Copper: copper has large toughness and good wear resistance. It is suitable for rough grinding valves with large machining allowance and low roughness requirements. It can play the role of low carbon steel grinding tool (but it is rarely used due to high cost).

鋁：鋁質地比銅軟，適用于銅等軟金屬的精細研磨。

Aluminum: aluminum is softer than copper. It is suitable for fine grinding of soft metals such as copper.

鉛、巴氏合金：適用于拋光和研磨軟鋼或其他軟質材料的工件。

Lead and Babbitt alloy: suitable for polishing and grinding workpieces of mild steel or other soft materials.

玻璃：玻璃質地硬脆，適用于工件的研磨和拋光，特別是淬硬鋼的精研。

Glass: glass is hard and brittle. It is suitable for grinding and polishing of workpieces, especially for fine grinding of hardened steel.

瀝青：瀝青質地軟，適用于玻璃、水晶等脆硬材料的研磨和拋光船用閥門，也適用于淬硬鋼的精拋光加工。瀝青對工件形狀適應性強。

Asphalt: asphalt is soft and suitable for grinding and polishing of brittle and hard materials such as glass and crystal. It is also suitable for fine polishing of hardened steel. Asphalt has strong adaptability to workpiece shape.

皮革、毛氈、滌淪織物：質地柔軟，常用于拋光工件。滌淪織物平整均勻，襯墊在平整的研具上，精研和拋光的效果好。

Leather, felt, polyester fabric: soft texture, commonly used for polishing workpieces. The polyester fabric is flat and uniform, and the pad is on the flat grinding tool, which has a good effect of fine grinding and polishing.

為了節省材料、減少研具，研具常常制成兩用的，既可敷涂研磨劑，又可襯托砂布或砂紙。專門襯托砂布或砂紙的研具，一般用碳鋼、鑄鐵制成。

In order to save materials and reduce grinding tools, grinding tools are often made into dual-purpose tools, which can not only apply abrasive, but also set off abrasive cloth or sandpaper. Grinding tools specially used to set off abrasive cloth or sandpaper are generally made of carbon steel and cast iron.