304基本型金属四氟复合垫金属缠绕垫片一般采用和缠绕钢带相同材料符合管道介质耐腐蚀要求通常优于管道或法兰的材料，根据标准要求先将金属缠绕带固定在内环上然后用金属缠绕带与石墨、石棉、四氟、无石棉等非金属缠绕带不断相互交替重迭螺旋缠绕而成，在末端用点焊方式将金属带固定。内环又叫加强环以避免缠绕垫片的散圈。
304基本型金属四氟复合垫
下表是缠绕垫片直径公差（即用于法兰的名义管道直径）：
DIN (mm)ANSI B16.5
BS1560 (mm)
Mss sp-44API 605公差内环内径
垫片内径<=600<=24">=26" and <=34"±0.5>600 and <=800>24" and <=34">=36" and <=60"±0.9>800 and <=1600>34" and <=60" ±1.3>1600>60" ±1.6垫片外径<=600<=24"<=24"±0.9>600 and <=16000>24" and <=60">24" and <=60"±1.81600>60" ±2.2外环外径 >=1/2" and <=60"±0.9<=600<=24" 0-1.0>600 and <=1000>24" and <=34" 0-1.8>1000 and <=1600">34" and <=60 0-2.2
材料:
1.带内环金属缠绕垫片金属带
A. 采用厚度为0.15mm~0.25mm的, sus304,sus316L,sus321等冷轧钢带，或由供需双方协商确定。
B. 金属带为预成型的V型或W型窄带，表面应光滑.洁净，不应有粗糙不平.裂纹.划伤.凹坑及锈斑等缺陷
C.不锈钢的硬度值 HV≤200