螺母的結構尺寸與公差按相應标準圖樣的規定，一般公差按 GB/T 1804-2000 中m級的規定。
螺母螺紋的基本尺寸按 GB/T 196 的規定，螺紋的公差按 GB/T 197 的規定，粗牙為 5H，細牙為 6H 。
螺紋孔兩端應進行倒角，倒角角度約等于120°，倒角直徑約等于螺紋大徑，見圖1。
金屬絲孔的尺寸按相應标準圖樣規定，孔的型式按 QJ 834-1988 的規定。
4.1. 螺母支承面的平面度公差為 0.05mm ，不允許中問部分的材料向外凸起。
4.2. 螺母支承面對螺紋軸線的垂直度按 圖2 和 表2 的規定。
表2 螺母支承面的垂直度 （單位：毫米)
| 對邊寬度S | ≤ 5 | ＞5~14 | ＞14~20 | ＞20~23 | ＞23 |
| 垂直度 t | 0.08 | 0.10 | 0.13 | 0.15 | 0.18 |
4.3 螺母的對稱度按圖3 和表3 規定。
表3 螺母的對稱度
| 螺紋規格 | M2~M3 | M4~M6 | M8 | M10 | M12×1.5 M14×1.5 | M16×1.5 M18×1.5 | M20×1.5~M24×1.5 |
| 對邊對稱度 t1 | 0.25 | 0.3 | 0.36 | 0.43 | 0.52 | ||
| 開槽對稱度 t2 | / | 0.2 | 0.25 | 0.3 | |||
螺母的表面處理種類按相應标準圖樣的規定。表面處理的厚度和技術條件按 表4 的規定。允許螺紋表面、金屬絲孔表面和開槽螺母的槽内表面的鍍層厚度小于 表4 的規定值。
表4 螺母的表面處理
| 材料 | 種類 | 鍍（塗）層厚度 | 技術條件 | |
| 碳鋼 | 鋼45 | 鍍鋅鈍化 | 螺距 P ≤ 0.8 mm：4 μm ~ 7 μm 螺距 P > 0.8 mm：7 μm ~ 12 μm | QJ452 |
| 合金鋼 | 30CrMnSiA | |||
| 高溫合金 | GH2132 | 鍍銀 | QJ458 | |
| 鈍化 | / | QJ467 | ||
| 不鏽鋼 | 1Cr17Ni2 0Cr18Ni9 | 鈍化 | / | |
| 钛合金 | TB3 | 硼化加 MoS2 潤滑處理 | 3 μm ~ 8 μm | 相關工藝文件 |
銀鍍層經結合力試驗後，不應出現起皮或剝落現象。
螺母的外觀質量應符合下列要求：
a ）螺母的表面粗糙度應符合相應标準圖樣的規定。螺紋的表面粗糙度Ra 的上限值為3.2μm;
b ）螺母表面不允許有裂紋：
c ）螺母的側面允許有深度不超過表5 規定的條痕或發紋等不連續性缺陷，允許的表面不連續性缺陷的型式見附錄A;
d ）螺母表面應光潔，無毛刺。
表5 螺母的表面不連續性缺陷
| 螺紋規格 | M2~M3 | M4, M5 | M6 | M8, 10 | M12×1.5 | M14×1.5 | M16×1.5~M22×1.5 | M24×1.5 |
| 表面缺陷的最大深度 | 0.10 | 0.12 | 0.13 | 0.15 | 0.20 | 0.22 | 0.25 | 0.30 |
對由合金鋼制造的螺母應在螺母側面制材料标志，見圖4 。标志應制成凹陷形，尺寸按表6 。
表6 材料标志的尺寸
| 螺紋規格 | M5~M8 | M10,M12×1.5~M20×1.5 | M22×1.5, M24×1.5 |
| l (參考) | 1.8~2.3 | 2~3 | 3~5 |
Specifications of high strength bolts with large hexagon head, large hexagon nuts, plain washers for steel structures
Self-tappingscrew connections - Specification ofthepilotholediameterand tighteningtorque
Composite sealing gasket material
Corrosion of metals and alloys - Corrosivity of atmospheres - Part 1 : Classification, determination and estimation
Corrosion of metals and alloys - Corrosivity of atmospheres - Part 2: Guiding values for the corrosivity categories
Steel wire ropes for general purposes
Specifications for spring washers - Conical spring washers
Specifications for retaining rings-Circlips
Hot formed helical compression springs - Technical Requirement
High-strength structural bolting assemblies for preloading - Part 1: General requirements
Cold coiled helical springs technical specifications - Part 1: Extension spring
Cold coiled helical springs technical specifications - Part 2: Compressions spring
Specification For Wire Thread Inserts
General specifications for packing of mechanical and electrical product
Fasteners - General requirements for bolts,screws,studs and nuts
24° Cone Connectors - Specification
Flared couplings - Specification
Specification of metallic ring-joint gaskets for steel pipe flanges
Specifications of high strength bolts with large hexagon head, large hexagon nuts, plain washers for steel structures
Specification of gauges for general purpose screw threads
Fasteners - Marking and packaging
Plain Washers for Bolts, Screws and Nuts - General Plan
Fasteners - Surface discontinuities - Bolts, screws and studs for general requirements
Fasteners-Surface discontinuities - Nuts
Fasteners - Surface discontinuities - Bolts, screws and studs for special requirements
Technical requirements for anchors
Specifications For Drive Rivets
Technical requirement for sets of torshear type high strength bolt hexagon nut and plain washer for steel structures
Specifications for parts and units of jigs and fixtures
Grease nipples and lubricating cups technical specification
Oil level indicators technical specification
Counterbores for hexagon socket head and slotted cheese head screws
Procurement Specification For Self-Locking Nuts
Specification for tab washer
Specifications for pins
Spcifications for ring - Cutting rings
Technical requirements of malleable cast iron pipe fittings
Fasteners - Part 27: Steel screws, bolts and studs made of steel with pre-adhesive coating - Technical specifications
metal washers; technical delivery conditions
Steel flat products; Hot rolled plate 3 to 150 mm thick; Permissible deviations of dimension, weight and form
Flat products of steel; cold rolled steel strip; dimensions, tolerances on dimensions and form.
Commercial vehicles - Wheel-hub attachment dimensions
Corrosion of metals and alloys - Corrosivity of atmospheres - Guiding values for the corrosivity categories
Tools for pressing - Elastomer pressure springs - Part 2: Specification of accessories
Hydraulic fluid power - Two-, three- and four-port screw-in cartridge valves - Cavities
Cold heading dies for fasteners - Specifications
Specification of Stamping Die Components
Specifications for parts and units of jigs and fixtures
Internal combustion engines - Cylinder head and flywheel nuts - Specifications
Timber structures - Dowel-type fasteners - Requirements
Aerospace series - Bolts, MJ threads, in heat resisting nickel base alloy NI-PH2601 (Inconel 718) - Classification: 1275 MPa (at ambient temperature)/650 °C - Technical specification
High-strength structural bolting assemblies for preloading - Part 1: General requirements
Flanges and their joints - Bolting - Part 3: Classification of bolt materials for steel flanges, class designated
Metallic products - Types of inspection documents
Flanges and their joints - bolting - Part 2: Classification of bolt materials for steel flanges, PN designated
Flanges and their joints - bolting - Part 1: Selection of bolting
Aerospace series - Inserts, screw thread, helical coil, self locking - Technical specification
Aerospace series - Inserts, screw thread, helical coil, self-locking - Assembly procedure
Specification for Selection of Steel Pipe Flanges , Gaskets and Bolting (PN designated)
Alloy and Carbon Steel Bolting for Use in the Petroleum and Natural Gas Industries
Standard Specification for Steel Transmission Tower Bolts, Zinc-Coated and Bare
Mechanical fixation component for waterproofing membrane roofing
Construction machinery and equipment Specification of high strength fasteners
Fastenersart - Standard - Cap Screws, Hex Bolts, and Hex Nuts
Steel Self-Drilling Tapping Screws
Technical conditions for threaded fasteners with adhesive coating-Part 1: Microencapsulated locking coating
Technical condions for threaded fasteners with adhesive coating-Part 2: Polyamlde locking coating
Technical Supply Conditions For Threaded Steel Fasteners - Part 1 General Requirements For Bolts, Screws And Studs
General data for machine screws and tapping screws
Disc springs - Calculation
