251 gb/t 1168-1976 螺柱技术条件 studs——technical requirements

　　252 gb/t 1228-1991 钢结构用高强度大六角头螺栓 high strength bolts with large hexagon head for steel structures 253 gb/t 1229-1991 钢结构用高强度大六角螺母 high strength large hexagon nuts for steel structures

　　254 gb/t 1230-1991 钢结构用高强度垫圈 high strength plain washers for steel structures

　　255 gb/t 1231-1991 钢结构用高强度大六角头螺拴、大六角螺母、垫圈技术条件 specifications of high strength bolts with large hexa-gon head, large hexagon nuts, plain washers for steel structures

　　256 gb/t 1237-1988 紧固件的标记方法 designation system for fasteners

　　257 gb/t 1337-1988 六角自锁螺母 self-locking nuts,hexagon

　　258 gb/t 1338-1988 小六角扁自锁螺母 self-locking nuts,reduced hexagon oblate

　　259 gb/t 1339-1988 小六角自锁螺母 self-locking nuts,reduced hexagon

　　260 gb/t 1340-1988 成组游动托板自锁螺母支架 supports for self-locking nuts,anchor floating,gang channel

　　261 gb/t 1356-1988 淅开线圆柱齿轮 基本齿廓 basic rack tooth profile of involute cylindrical gears

　　262 gb/t 1357-1987 渐开线圆柱齿轮模数 modules of involute cyindrical gears

263 gb/t 1563-1979 楔键 键和键槽的剖面尺寸 taper keys——cross section dimensions of keys and keyways

　　264 gb/t 1564-1979 普通楔键 型式尺寸 taper keys for general use——types and dimensions

　　265 gb/t 1565-1979 钩头楔键 型式尺寸 gib-head taper keys——types and dimensions

　　266 gb/t 1566-1979 薄型平键 键和键槽的剖面尺寸 thin flat keys——cross section dimensions and keyways

　　267 gb/t 1567-1979 薄型平键 型式尺寸 thin flat keys——types and dimensions

　　268 gb/t 1840-1989 圆弧圆柱齿轮模数 modules of cylindrical gear with circular arc profiles

　　269 gb/t 1974-1980 切向键及其键槽 tangential keys and keyways

　　270 gb/t 2362-1990 小模数渐开线圆柱齿轮基本齿廓 basic rack tooth profile of fine-pitch involute cylindrical gears 271 gb/t 2363-1990 小模数渐开线圆柱齿轮精度 accuracy of fine-pitch involute cylindrical gears

　　272 gb/t 2509-1981 滑动轴承铜合金整体轴套形式、尺寸与公差 copper alloy integrated shaft sleeves for plain bearings——types, dimensions and tolerances

　　273 gb/t 2510-1981 滑动轴承铜合金带挡边整体轴套形式、尺寸与公差 copper alloy integrated shaft sleeves for plain bearings with gears——types, dimensions and tolerances

　　274 gb/t 2511-1981 滑动轴承铜合金整体轴套技术条件 copper alloy integrated shaft sleeves——technical requirements

　275 gb/t 2555-1981 一般用途管法兰连接尺寸 pipe flange connectors for ordinary use——mounting dimensions

　　276 gb/t 2556-1981 一般用途管法兰密封面形状和尺寸 pipe flanges for ordinary use——sealing surfaces——forms and dimensions

　　277 gb/t 2672-1986 内六角花形盘头螺钉 hexagon lobular socket pan head screws

　　278 gb/t 2673-1986 内六角花形沉头螺钉 hexagon lobular socket countersunk head screws

　　279 gb/t 2674-1986 内六角花形半沉头螺钉 hexagon lobular socket raised countersunk head screws

　　280 gb/t 2685-1981 滑动轴承 粉末冶金筒形轴承型式、尺寸与公差 powder metallurgy plain bearing——cylindrical type——types, dimensions and tolerances

　　281 gb/t 2686-1981 滑动轴承 粉末冶金带挡边筒形轴承型式、尺寸与公差 powder metallurgy plain bearing——rimed cylindrical type——types, dimensions and tolerances

　　282 gb/t 2687-1981 滑动轴承 粉末冶金球形轴承型式、尺寸与公差 powder metallurgy plain bearing——spherical type——types, dimensions and tolerances

　　283 gb/t 2688-1981 滑动轴承 粉末冶金轴承技术条件 powder metallurgy plain bearing——technical requirements

　　284 gb/t 2821-1992 齿轮几何要素代号 symbols for gear geometrical data

　　285 gb/t 2889-1994 滑动轴承 术语 plain bearings——terms, definitions and classification

　　286 gb/t 3098.1-1982 紧固件机械性能 螺栓、螺钉和螺柱 mechanical properties of fasteners——bolts, screws and studs

　287 gb/t 3098.2-1982 紧固件机械性能 螺母 mechanical properties of fasteners——nuts

　　288 gb/t 3098.3-1982 紧固件机械性能 紧定螺钉 mechanical properties of fasteners——set screws

　　289 gb/t 3098.4-1986 紧固件机械性能——细牙螺母 mechanical properties of fasteners——nuts with fine pitch thread

　　290 gb/t 3098.5-1985 紧固件机械性能 自攻螺钉 mechanical properties of fasteners——tapping screws

　　291 gb/t 3098.6-1986 紧固件机械性能 不锈钢螺栓, 螺钉, 螺柱和螺母 mechanical properties of fasteners——stainless steel bolts,screws, studs and nuts

　　292 gb/t 3098.7-1986 紧固件机械性能 自攻锁紧螺钉 粗牙普通螺纹系列 mechanical properties of fasteners——thread forming screws——metric coarse thread series

　　293 gb/t 3098.8-1992 紧固件机械性能 耐热用螺纹连接副 mechanical properties of fasteners——components for bolted connections made mainly from materials with a high temperature strength

　　294 gb/t 3098.9-1993 紧固件机械性能有效力矩型钢六角锁紧螺母 mechanical properties of fasteners——prevailing torque type steel hexagon nuts

　　295 gb/t 3098.10-1993 紧固件机械性能 有色金属制造的螺栓、螺钉、螺柱和螺母 mechanical properties of fasteners——bolts, screws, studs and nuts made of non-ferrous metals

　　296 gb/t 3098.11-1995 紧固件机械性能自钻自攻螺钉 mechanical properties of fasteners——self-drilling tapping screws

297 gb/t 3098.13-1996 紧固件机械性能 螺栓与螺钉的扭矩试验和破坏扭矩公称直径1~10mm mechanical properties of fasteners——torsional test and minimum torques for bolts and screws with nominal diameters 1mm to 10mm

　　298 gb/t 3098.12-1996 紧固件机械性能 螺母锥形保证载荷试验 mechanical properties of fasteners——cone proof load test on nuts

　　299 gb/t 3099-1982 螺栓、螺钉、螺母及附件名词术语 bolts, screws, nuts and accessories——terminology and nomenclature

　　300 gb/t 3103.1-1982 紧固件公差 螺栓、螺钉和螺母 tolerances for fasteners——bolts, screws and nuts