एक फास्टनर क्या है? प्रकार, अनुप्रयोग और चयन गाइड

बोल्ट और स्क्रू के बीच क्या अंतर है?

A: एक बोल्ट को क्लीयरेंस होल के माध्यम से डालने और अखरोट के साथ कसने के लिए डिज़ाइन किया गया है, जबकि एक स्क्रू मैट सीधे एक थ्रेड के साथ एक भागों में शामिल होने या उसके खुद के थ्रेड बनाता है क्योंकि यह संचालित होता है। यह भेद इस बारे में है कि यह कैसे दिखता है, इसके बजाय इसका उपयोग कैसे किया जाता है, यही कारण है कि बाहरी रूप से थ्रेडेड भाग को संयुक्त के आधार पर या तो बुलाया जा सकता है। व्यावहारिक शब्दों में, एक बोल्ट संयुक्त को अखरोट की तरफ से कस दिया जाता है और एक स्क्रू संयुक्त को सिर की तरफ से कस दिया जाता है। दोनों ही समान clamping बल बनाते हैं।.

फास्टनर के मुख्य प्रकार क्या हैं?

A: मुख्य समूह हैं थ्रेडेड फास्टनर, जिसमें बोल्ट, स्क्रू, स्टड, जेडजेड 1 जेडजेड और नट्स शामिल हैं; गैर थ्रेडेड फास्टनरों, जिसमें rivets, पिन, एंकर और बनाए रखने के छल्ले शामिल हैं; और सहायक भागों जैसे वाशर जो संयुक्त समर्थन करते हैं। थ्रेडेड फास्टनरों के भीतर वर्गीकरण सिर शैली, ड्राइव टाइप, थ्रेड फॉर्म, सामग्री और अनुप्रयोग द्वारा चलता है। अधिकांश औद्योगिक असेंबली एक बोल्ट या स्क्रू का उपयोग एक नट या टैप होल के साथ करते हैं, साथ ही भार को फैलाने के लिए वॉशर भी।.

सबसे आम फास्टनर सामग्री क्या है?

A: कार्बन स्टील सबसे आम फास्टनर सामग्री है क्योंकि यह प्रति यूनिट लागत और आकार और सिर शैलियों में व्यापक उपलब्धता प्रदान करता है। इसकी कमजोरी जंग है, इसलिए यह लगभग हमेशा एक कोटिंग जैसे कोटिंग के साथ आपूर्ति की जाती है। जस्ता चढ़ाना for outdoor or humid service. Stainless steel is the next most common where corrosion resistance matters, followed by alloy steel for high strength, aluminium and titanium for weight saving, and plastics for electrical or chemical isolation.

How do I choose the right fastener size?

A: Work from the joint backwards. Measure the total stack thickness, add the nut height plus two or three threads of protrusion, and that is your minimum length. Choose the diameter from the load, using the property class to set how much clamp load the section can carry, then check the thread engagement length: around one times the diameter in steel, roughly 1.5 times in aluminium, and more in plastics. Finally confirm the pitch, because a fine pitch nut will start on a coarse thread and then seize.

What does a fastener grade number mean?

A: On metric carbon steel fasteners the grade is a property class such as 8.8 or 10.9, where the first number times 100 gives the minimum tensile strength in MPa and the second number times 10 gives the yield to tensile ratio. So an 8.8 bolt has a minimum tensile strength of 800 MPa and yields at 80 percent of that. Inch series fasteners use SAE grades such as 2, 5, and 8, and stainless uses codes such as A2-70 or A4-70, where 70 means 700 MPa tensile.

What is the difference between metric and imperial fasteners?

A: Metric fasteners are designated by a nominal diameter in millimetres and a thread pitch in millimetres, such as M10 x 1.5, while imperial fasteners use a fractional diameter and threads per inch, such as 1/2-13 UNC. The two are not interchangeable even at similar diameters, because the pitch and, in some cases, the thread angle differ. Metric parts follow ISO dimensional standards and inch parts follow ASME or SAE, so the required tools and washers differ as well.

Are fasteners and hardware the same thing?

A: Not quite. Fastener refers to a device whose primary function is to join or secure components, such as a bolt, screw, nut, washer, rivet, or anchor. Hardware is a broader trade term that can include fasteners along with brackets, hinges, handles, and other items that support an assembly without joining it. In purchasing practice the two words often overlap, and some suppliers list fasteners as a subcategory of hardware.

How do you stop a fastener from loosening?

A: Loosening from vibration happens when transverse movement lets the nut rotate back slightly on each cycle, so the fix is to keep either the preload or the relative motion. Options include a prevailing torque nut or screw, a wedge lock or serrated washer, a thread locking compound, a castellated nut with a split pin, or a safety wire in aerospace practice. Tightening to the correct preload in the first place matters more than any locking device, because a joint with enough clamp load rarely loosens on its own.

What is the difference between a permanent and a removable fastener?

A: A removable fastener, such as a bolt with a nut or a screw into a tapped hole, can be disassembled and refitted without destroying the part or the joint. A permanent fastener, such as a solid or blind rivet, a clinch nut, or a welded stud, is designed to stay in place and must be drilled out or cut away for removal. The choice depends on whether the assembly will need servicing, adjustment, or disassembly for shipping at any point in its life.

What is clamp load and why does it matter?

A: Clamp load is the compressive force that a tightened fastener applies to the joint, produced by stretching the bolt when it is torqued. It matters because a properly clamped joint transfers shear load through friction between the plates rather than through the bolt shank, which is what keeps the fastener from seeing fatigue loading. If clamp load is lost through loosening, relaxation, or embedding, the joint starts to slip and the bolt begins to carry alternating load, which is how most bolted joints eventually fail.