---
title: "What Are Engineered Component Used For?"
description: "Engineered Components (GB/T 78 / ISO 4027) are used for a specific function defined by the part drawing rather than by a catalog fastener standard."
url: https://engineeringhardware.com/applications/cad-svg-025-genericpart/
source: Engineering Hardware & Fasteners
---

# What Are Engineered Component Used For?

General Components · GB/T 78 / ISO 4027 · Application guide

Typical applications, the industries that specify engineered component, and how to choose the right size, material and finish for the joint.

Engineered Components are used for a specific function defined by the part drawing rather than by a catalog fastener standard. They are manufactured to GB/T 78 / ISO 4027, and selection is driven by the nominal size, the fit and tolerance the assembly requires, and the service environment.

- **Primary duty:** A specific function defined by the part drawing rather than by a catalog fastener standard
- **Governing standard:** GB/T 78 / ISO 4027
- **Nominal size range:** Size 1 to Size 8
- **Category:** General Components

Application notes are general engineering guidance. Verify the property class and any approval requirement against your own design calculation.

![What Are Engineered Component Used For? application image](https://engineeringhardware.com/wp-content/uploads/2026/06/086-Engineered-Component-—-GB／T-78-／-ISO-4027-Series-025-—-GB／T-78-／-ISO-4027.webp)

Engineered Components (GB/T 78 / ISO 4027) are specified where the joint requires a specific function defined by the part drawing rather than by a catalog fastener standard. The sections below cover the typical end-uses by industry, the size and material decisions for each, assembly practice, and the applications this fastener type is not suited to. Stocked across roughly 1 mm to 8 mm, they cover general to heavy-duty work.

## Typical Applications for Engineered Component — GB/T 78 / ISO 4027 (Series 025)

The most common settings where these are specified:

- **General machine building:** fastening covers, brackets, motors and sub-assemblies on production equipment.
- **Maintenance & repair (MRO):** a stocked size for servicing existing plant where the original fastener spec must be matched.
- **Fabrication & metalwork:** bench and on-site assembly of steel frames, enclosures and weldments.

## How to Specify Engineered Component — GB/T 78 / ISO 4027 (Series 025) for Your Application

- **Size:** Select on nominal size, and confirm it against the mating feature in the assembly. This product spans 1 mm–8 mm; check the full table below for the exact dimensions of each size.
- **Material:** Choose the material and finish for the service environment — plated steel for general use, stainless for corrosion resistance.
- **Environment:** For damp, coastal or chemical exposure prefer A4/316 stainless or a suitable coating; indoors, plated steel or A2 is usually sufficient.
- **Standard:** This product is supplied to GB/T 78 / ISO 4027. Quoting the standard on your order guarantees interchangeable dimensions between suppliers.

## Where Engineered Component — GB/T 78 / ISO 4027 (Series 025) Are Not the Right Choice

Match the fastener to the load, environment and whether the joint must be reopened; the wrong class or style is the usual cause of joint failure.

Custom manufacturing · Made to drawing

## Need a engineered component outside the standard range?

The geometry is whatever the drawing says. A machined component has no standard to depart from, so the drawing and the tolerance scheme are the whole specification. Made by warm forging or thread turning.

Minimum order from 2,000 pieces; samples within 7 days of drawing approval.

[Custom machined component manufacturing](https://engineeringhardware.com/custom/components/)[Send a drawing](https://engineeringhardware.com/custom/components/#rfq)

## Technical Drawing

Dimensioned line drawing of Size 1 Engineered Component — GB/T 78 / ISO 4027 (Series 025) to GB/T 78 / ISO 4027. Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected.

- **Outer diameter / width (mm):** 10
- **Length / height (mm):** 20
- **Bore / thread (mm):** 6
- **Material:** C45 carbon steel

## Dimensions & Specifications (GB/T 78 / ISO 4027)

| Size designation | Outer diameter / width (mm) | Length / height (mm) | Bore / thread (mm) | Material | Reference standard |
| --- | --- | --- | --- | --- | --- |
| Size 1 | 10 | 20 | 6 | C45 carbon steel | GB/T 1804-m |
| Size 2 | 12 | 25 | 8 | C45 carbon steel | GB/T 1804-m |
| Size 3 | 16 | 32 | 10 | C45 carbon steel | GB/T 1804-m |
| Size 4 | 20 | 40 | 12 | C45 carbon steel | GB/T 1804-m |
| Size 5 | 25 | 50 | 16 | C45 carbon steel | GB/T 1804-m |
| Size 6 | 32 | 63 | 20 | C45 carbon steel | GB/T 1804-m |
| Size 7 | 40 | 80 | 25 | C45 carbon steel | GB/T 1804-m |
| Size 8 | 50 | 100 | 30 | C45 carbon steel | GB/T 1804-m |

Inside the plant

## Manufactured in our own plant

This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.

1. ![Wire rod feeding into a cold heading machine](https://engineeringhardware.com/wp-content/uploads/2026/08/09-wire-rod-feed-cold-heading-machine.webp) 01 **Cold heading** Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail. Head dimensions and under-head radius checked at set-up and per shift.
2. ![Thread rolling machine producing bolt threads](https://engineeringhardware.com/wp-content/uploads/2026/08/03-thread-rolling-machine-bolt-production.webp) 02 **Thread rolling** Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch. Go / no-go ring gauges to ISO 965 tolerance class 6g.
3. ![Baskets of bolts staged for heat treatment](https://engineeringhardware.com/wp-content/uploads/2026/08/05-heat-treatment-baskets-black-bolts.webp) 03 **Heat treatment** Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it. Core hardness and tensile tested per lot to ISO 898-1.
4. ![Zinc plated bolts in a treatment basket](https://engineeringhardware.com/wp-content/uploads/2026/08/23-zinc-plated-bolts-treatment-basket.webp) 04 **Surface treatment** Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list. Coating thickness and neutral salt spray hours to ISO 9227.

## Frequently Asked Questions

### What are Engineered Component — GB/T 78 / ISO 4027 (Series 025) used for?

A specific function defined by the part drawing rather than by a catalog fastener standard. They are supplied to GB/T 78 / ISO 4027.

### Which industries use Engineered Component — GB/T 78 / ISO 4027 (Series 025)?

They are commonly specified in general machine building, maintenance & repair (mro) and fabrication & metalwork, among other sectors.

### How do I choose the right size of Engineered Component — GB/T 78 / ISO 4027 (Series 025)?

Select on nominal size and on the fit the assembly requires. This product is available from 1 mm to 8 mm; the full dimension table on this page lists each size.

### Are Engineered Component — GB/T 78 / ISO 4027 (Series 025) made to a recognized standard?

Yes — they are manufactured to GB/T 78 / ISO 4027, so dimensions are interchangeable between suppliers when you quote the standard on your order.

### Can I get a quote for Engineered Component — GB/T 78 / ISO 4027 (Series 025) in the size and material I need?

Yes. Use the technical drawing and quote form on this page to set the size and options, then send the exact configuration to our team for pricing and lead time.

## Related Pages

Product page: [Engineered Component — GB/T 78 / ISO 4027 (Series 025) — specifications & sizes](https://engineeringhardware.com/fastener/cad-svg-025-genericpart/)

### Engineered Component — GB/T 78 / ISO 4027 (Series 025) Specification Guides

### Related Fastener Applications