📚 OCR Engineering Glossary Quick-Study Guide | OCR 工程词汇速记指南
Mastering the language of engineering is essential for Year 11 OCR candidates. This glossary demystifies key technical terms, linking them directly to concepts you’ll meet in materials, mechanics, manufacturing, and systems. Use it as a rapid revision tool to strengthen your exam answers and design justifications.
掌握工程语言对 Year 11 OCR 考生至关重要。这份术语表解析了关键专业词汇，将它们直接与你将在材料、力学、制造和系统中遇到的概念联系起来。可用作快速复习工具，以强化你的考试答案和设计论证。
1. Materials & Properties | 材料与性能
The selection of materials depends on their mechanical and physical properties. Engineers test hardness, toughness, ductility, and stiffness to predict how a material will behave under service conditions.
材料的选择取决于其力学与物理性能。工程师通过测试硬度、韧性、延性和刚度来预测材料在使用条件下的表现。
Toughness is the ability to absorb energy and deform plastically before fracturing. It is measured by impact tests such as the Charpy test. A tough material can withstand sudden shocks without cracking.
韧性 是指材料在断裂前吸收能量并发生塑性变形的能力。可通过夏比冲击试验测量。韧性材料能承受突然冲击而不破裂。
Ductility refers to how much a material can be stretched or drawn into a wire without breaking. High ductility is critical for forming processes like wire drawing and deep drawing of sheet metal.
延性 指的是材料能被拉伸或拉成丝而不断裂的能力。高延性对于拉丝和金属板深冲等成形工艺至关重要。
Hardness is the resistance to indentation, scratching, or wear. Common scales include Brinell, Vickers, and Rockwell. Hard materials resist surface deformation but may be brittle.
硬度 是对压入、划伤或磨损的抵抗能力。常用标度有布氏、维氏和洛氏硬度。硬材料能抵抗表面变形，但可能较脆。
Elasticity is the ability to return to original shape after the removal of a load. The limit of this behaviour is the elastic limit, beyond which permanent deformation occurs.
弹性 是卸除载荷后恢复原始形状的能力。这种行为的极限是弹性极限，超过此点将发生永久变形。
2. Stress, Strain & Young’s Modulus | 应力、应变与杨氏模量
When a force is applied to a component, internal resistance builds up. Stress quantifies this internal force per unit area, while strain describes the resulting deformation.
当力施加在构件上时，内部会产生抗力。应力量化了单位面积上的这种内力，而应变则描述了由此产生的变形。
Stress (σ) is defined as force divided by cross-sectional area. Its unit is the pascal (Pa) or N/m². Tensile stress pulls atoms apart, compressive stress pushes them together, and shear stress causes layers to slide.
应力 (σ) 定义为力除以横截面积。单位是帕斯卡 (Pa) 或 N/m²。拉伸应力使原子分离，压应力使原子靠近，剪应力则使层间滑动。
Strain (ε) is a dimensionless ratio of change in length to original length. It is often expressed as a percentage. Elastic strain is reversible, while plastic strain remains after unloading.
应变 (ε) 是长度变化量与原始长度的无量纲比值。通常以百分比表示。弹性应变可逆，而塑性应变在卸载后仍存在。
Young’s modulus (E) equals stress divided by strain in the elastic region. It measures stiffness: a high modulus means a material resists stretching and bending. The formula is displayed as:
杨氏模量 (E) 等于弹性区域内应力除以应变。它测量刚度：高模量意味着材料能抵抗拉伸和弯曲。公式展示为：
E = σ / ε
3. Common Loading Modes | 常见载荷形式
Understanding how a structure carries load is vital. Tension, compression, bending, shear, and torsion each create distinct stress patterns that dictate the shape and material of a component.
理解结构如何承载至关重要。拉伸、压缩、弯曲、剪切和扭转各自产生不同的应力分布，这决定了构件的形状和材料。
Tension pulls along the longitudinal axis, as seen in crane cables and tie rods. Compression shortens a member, typical in columns and struts. Both can cause failure by yielding or buckling.
拉伸 沿纵轴拉拽，例如起重机缆绳和拉杆。压缩 使构件缩短，常见于柱和支柱。两者均可能因屈服或屈曲而失效。
Bending combines tension on one side and compression on the other. Beams and axles experience bending moments. The maximum stress occurs at the outer surface, which is why I-beams are shaped to put more material there.
弯曲 使一侧受拉、另一侧受压。梁和车轴承受弯矩。最大应力发生在外表面，因此工字梁的形状旨在将更多材料置于此处。
Shear occurs when parallel forces act in opposite directions, like scissors cutting paper. Rivets and bolts are designed to resist shear loads. Torsion twists a shaft; drive shafts and screwdrivers experience shear stress distributed radially.
剪切 发生在反向平行力作用时，如剪刀剪纸。铆钉和螺栓被设计用来抵抗剪切载荷。扭转 使轴产生扭转变形；传动轴和螺丝刀承受沿径向分布的剪应力。
4. Failure Mechanisms | 失效机制
Beyond simple overload, materials can fail over time due to fatigue, creep, or environmental attack. Identifying these mechanisms in a design context is a key OCR exam skill.
除了简单的过载，材料还可能因疲劳、蠕变或环境侵蚀而随时间失效。在设计背景中识别这些机制是 OCR 考试的关键技能。
Fatigue is the progressive and localised damage caused by repeated cyclic loading. Even if each cycle is below the yield stress, microscopic cracks grow until sudden fracture occurs. Rotating shafts, aircraft wings, and bridges are fatigue-critical.
疲劳 是由重复循环载荷引起的渐进式局部损伤。即使每个循环都低于屈服应力，微观裂纹也会扩展直至突然断裂。旋转轴、机翼和桥梁都属于疲劳关键部件。
Creep is the slow, permanent deformation under constant stress at high temperature. Turbine blades in jet engines suffer creep. The creep rate accelerates as temperature increases, so materials with high melting points are chosen.
蠕变 是高温下在恒定应力作用下发生的缓慢永久变形。喷气发动机中的涡轮叶片会发生蠕变。蠕变速率随温度升高而加快，因此会选择熔点高的材料。
Corrosion is the chemical degradation of a metal by reaction with its environment. Rusting of iron requires oxygen and water. Protective coatings, cathodic protection, and alloying (e.g., stainless steel) are used to prevent corrosion.
腐蚀 是金属与环境发生化学反应而导致的降解。铁生锈需要氧气和水。可通过保护涂层、阴极保护和合金化（如不锈钢）来防止腐蚀。
5. Ferrous and Non-Ferrous Metals | 黑色金属与有色金属
OCR Engineering expects you to classify metals and explain how their composition affects properties. Ferrous metals contain iron, which makes them magnetic and often prone to rust. Non-ferrous metals offer lighter weight and corrosion resistance.
OCR 工程学要求你对金属进行分类，并解释其成分如何影响性能。黑色金属含铁，因此有磁性且易生锈。有色金属重量更轻且耐腐蚀。
Low-carbon steel (mild steel) contains up to 0.3% carbon. It is tough, ductile, and easy to weld, making it the workhorse for structural sections and car bodies. High-carbon steel (0.6–1.4% C) is much harder and is used for cutting tools and springs.
低碳钢（软钢） 含碳量最高 0.3%。它韧、延性好且易于焊接，是结构型材和车身的主力材料。高碳钢（0.6–1.4% C）硬度更高，用于切削工具和弹簧。
Cast iron contains 2–4% carbon and graphite flakes that make it brittle in tension but excellent in compression. It damps vibrations well, so it is used for machine tool beds and engine blocks.
铸铁 含碳量 2%–4%，其中的石墨片使其拉伸时较脆，但抗压能力优异。它吸振性能好，因此用于机床床身和发动机缸体。
Aluminium alloys are lightweight, corrosion-resistant, and easily extruded. Typical uses include aircraft frames, drink cans, and smartphone cases. Copper alloys like brass (Cu–Zn) and bronze (Cu–Sn) combine corrosion resistance with good conductivity.
铝合金 轻质、耐腐蚀且易于挤压。典型用途包括飞机骨架、饮料罐和手机壳。铜合金如黄铜（Cu–Zn）和青铜（Cu–Sn）兼具耐腐蚀性和良好导电性。
6. Heat Treatment | 热处理
Heating and cooling a metal in a controlled way alters its grain structure and mechanical properties. The three main processes are annealing, hardening (quenching), and tempering.
以可控方式加热和冷却金属会改变其晶粒结构和力学性能。三个主要工艺是退火、硬化（淬火）和回火。
Annealing involves heating a metal to a specific temperature, holding it, then cooling slowly in the furnace. It softens the metal, relieves internal stresses, and refines grain size. This improves ductility and machinability.
退火 包括将金属加热到特定温度、保温，然后在炉中缓慢冷却。它使金属软化，消除内应力并细化晶粒尺寸，从而改善延性和切削加工性。
Quenching rapidly cools a heated metal (usually in water, oil, or air). This traps carbon atoms in a distorted lattice, forming martensite, which is extremely hard but brittle. Tempering follows quenching: reheating at a lower temperature reduces brittleness while retaining most of the hardness.
淬火 是将加热后的金属快速冷却（通常在水、油或空气中）。这使碳原子被困在畸变的晶格中，形成马氏体，它极硬但脆。回火 随后进行淬火：在较低温度下重新加热，可降低脆性，同时保留大部分硬度。
Case hardening hardens only the surface while keeping the core tough. Techniques include carburising (adding carbon to the surface) and nitriding. Gear teeth and camshaft lobes are often case-hardened.
表面硬化 只使表层硬化而保持心部韧性。技术包括渗碳（向表面添加碳）和渗氮。齿轮齿和凸轮轴凸角常进行表面硬化处理。
7. Manufacturing Processes – Casting & Forming | 制造工艺 – 铸造与成形
Engineering relies on shaping processes that change raw material into useful components. Casting pours liquid metal into a mould; forming deforms solid material using force.
工程依赖于将原材料转变为有用构件的成形工艺。铸造将液态金属浇入模具；成形则利用力使固态材料变形。
Sand casting uses a sand mould to create complex shapes economically for low to medium volumes. A pattern shapes the cavity, and a pouring system feeds molten metal. Engine blocks and manhole covers are sand cast.
砂型铸造 使用砂模经济地制造中低批量的复杂形状。模样形成型腔，浇注系统导入金属液。发动机缸体和井盖就是砂铸件。
Die casting forces molten metal under high pressure into a steel die. It produces high-accuracy parts with smooth surfaces at high rates, suitable for zinc, aluminium, and magnesium alloys. Forging applies compressive forces to shape hot metal, aligning the grain flow and producing strong components such as spanners and connecting rods.
压力铸造 在高压下将熔融金属压入钢制模具。它能以高速率生产高精度、表面光滑的零件，适用于锌、铝和镁合金。锻造 施加压缩力使热态金属成形，使晶粒流线对齐，制造出扳手和连杆等强度高的构件。
Rolling passes metal between rollers to reduce thickness and make sheet, plate, or structural sections. Extrusion pushes a heated billet through a die to produce long profiles with constant cross-section, like window frames and heatsinks.
轧制 使金属通过轧辊以减少厚度，生产薄板、中厚板或结构型材。挤压 将加热的坯料推过模具，生产出截面不变的长型材，如窗框和散热片。
8. Machining & Material Removal | 机械加工与材料去除
Machining cuts material away from a workpiece to achieve tight tolerances and good surface finish. Turning, milling, drilling, and grinding are the core conventional processes.
机械加工从工件上切除材料，以实现高公差和良好的表面光洁度。车削、铣削、钻削和磨削是核心的传统工艺。
Turning rotates the workpiece while a single-point cutting tool moves parallel or perpendicular to the axis, producing cylindrical parts. It is performed on a lathe. Operations include facing, parting, and thread cutting.
车削 使工件旋转，单刃刀具平行或垂直于轴线移动，加工出圆柱形零件。它在车床上进行，操作包括端面车削、切断和螺纹切削。
Milling uses a rotating multi-tooth cutter to remove material from a stationary workpiece. Face milling creates flat surfaces; end milling cuts slots and profiles. CNC milling machines can produce complex 3D shapes.
铣削 使用旋转的多齿刀具从静止工件上切除材料。面铣加工平面；立铣加工槽和轮廓。数控铣床能生产复杂的三维形状。
Drilling creates or enlarges holes with a rotating bit. Grinding employs an abrasive wheel to achieve very smooth surfaces and precise dimensions. It is often used as a finishing process after heat treatment.
钻削 用旋转的钻头加工或扩大孔。磨削 使用砂轮获得非常光滑的表面和精确的尺寸，通常用作热处理后的精加工工序。
9. Joining Techniques | 连接技术
Permanent and semi-permanent joining techniques allow engineers to assemble multi-part products. OCR covers welding, brazing, soldering, and structural adhesives.
永久性和半永久性连接技术使工程师能够组装多零件产品。OCR 涵盖焊接、钎焊、软焊和结构粘合剂。
Welding fuses two metal pieces by melting them together, often with a filler rod, forming a strong joint as strong as the parent metal. Common methods are MIG (Metal Inert Gas), TIG (Tungsten Inert Gas), and spot welding for sheet metal.
焊接 通过熔化将两块金属熔合在一起，常使用填充棒，形成与母材等强度的牢固接头。常用方法有 MIG（熔化极惰性气体保护焊）、TIG（钨极惰性气体保护焊）和用于薄板焊接的点焊。
Brazing joins metals at a temperature above 450°C using a filler metal with a lower melting point. The filler is drawn into the joint by capillary action. Brazing is used for assemblies that would distort under welding heat.
钎焊 在 450°C 以上使用熔点较低的填充金属连接金属。填充金属通过毛细作用渗入接头。钎焊用于在焊接热量下易变形的组件。
Soldering is similar to brazing but at temperatures below 450°C. It is essential in electronics for making reliable electrical connections on PCBs. Adhesive bonding spreads stress over a larger area and can join dissimilar materials, such as carbon fibre to aluminium.
软焊 类似于钎焊，但温度低于 450°C。它对电子行业在 PCB 上形成可靠电气连接至关重要。粘合剂连接 将应力分散在更大面积上，并可连接异种材料，如碳纤维与铝。
10. Tolerances, Fits & Measurement | 公差、配合与测量
No part can be manufactured exactly to a nominal size. Tolerances define acceptable variation. Fits describe the relationship between a shaft and a hole.
任何零件都无法完全按名义尺寸制造。公差定义了可接受的偏差范围。配合描述了轴与孔之间的关系。
Tolerance 05 mm means the part can measure between 19.95 mm and 20.05 mm. Bilateral tolerance uses both plus and minus; unilateral uses only one direction.
公差 是尺寸允许的变动范围。标注 20 ±0.05 mm 意味着零件可测量在 19.95 mm 到 20.05 mm 之间。双向公差同时使用正负值；单向公差仅使用一个方向。
Clearance fit always leaves a gap (hole larger than shaft), allowing free rotation, as in a hinge. Interference fit requires force to assemble (shaft larger than hole), creating a tight fixed coupling. Transition fit may give either clearance or interference.
间隙配合 总留有间隙（孔大于轴），允许自由转动，如铰链。过盈配合 需要力来装配（轴大于孔），形成紧固定联结。过渡配合 可能产生间隙或过盈。
Measurement tools include vernier calipers (digital or analogue) for linear dimensions, micrometers for thickness and diameters, and dial indicators for checking runout and flatness. Coordinate Measuring Machines (CMM) use a probe to collect 3D point data.
测量工具包括测量线性尺寸的游标卡尺（数显或模拟式）、测量厚度和直径的千分尺，以及检查跳动和平面的百分表。三坐标测量机 (CMM) 使用测头采集三维点数据。
11. Automation, Control & Systems | 自动化、控制与系统
Modern engineering integrates mechanical hardware with electronic control. Understanding open-loop and closed-loop systems, sensors, and actuators is part of the OCR specification.
现代工程将机械硬件与电子控制相结合。理解开环与闭环系统、传感器和执行器是 OCR 大纲的一部分。
A sensor detects a physical quantity (temperature, pressure, position) and converts it into an electrical signal. Common types include thermocouples, strain gauges, and LVDTs. An actuator converts a control signal into motion: electric motors, hydraulic cylinders, and pneumatic rams.
传感器 检测物理量（温度、压力、位置）并将其转换为电信号。常见类型有热电偶、应变片和 LVDT。执行器 将控制信号转化为运动：电动机、液压缸和气动缸。
In an open-loop control system, output has no effect on the input. A washing machine timer runs a set cycle regardless of whether clothes are clean. A closed-loop (feedback) system continuously measures the output and adjusts the input. A domestic oven thermostat that turns the heating element on/off to maintain set temperature is an example.
在开环控制系统中，输出不影响输入。洗衣机定时器运行设定循环，无论衣物是否干净。闭环（反馈）系统 持续测量输出并调整输入。家用烤箱恒温器通过通断加热元件维持设定温度就是一个例子。
PLC (Programmable Logic Controller) is a rugged industrial computer used to automate machinery. It reads inputs, executes a ladder-logic program, and triggers outputs. Robots in manufacturing are programmed via PLCs or dedicated controllers.
PLC（可编程逻辑控制器）是用于自动化机械的坚固工业计算机。它读取输入，执行梯形逻辑程序并触发输出。制造业中的机器人通过 PLC 或专用控制器编程。
12. Design, CAD/CAM & Quality Systems | 设计、CAD/CAM 与质量体系
The design-and-make process relies heavily on digital tools and systematic quality management. OCR questions often ask you to explain how CAD/CAM improves productivity or how lean tools reduce waste.
设计与制造过程高度依赖数字工具和系统化的质量管理。OCR 考题常要求你解释 CAD/CAM 如何提高生产力，或精益工具如何减少浪费。
CAD (Computer-Aided Design) uses software to create precise 2D drawings and 3D models. Solid models allow analysis of mass, centre of gravity, and interference. CAM (Computer-Aided Manufacturing) converts CAD geometry into toolpaths for CNC machines, reducing human error and increasing consistency.
CAD（计算机辅助设计）使用软件创建精确的二维工程图和三维模型。实体模型可分析质量、重心和干涉情况。CAM（计算机辅助制造）将 CAD 几何体转换为数控机床的刀具路径，减少人为错误并提高一致性。
CNC (Computer Numerical Control) machines execute G-code instructions to move tools along precise trajectories. G-code commands specify feed rate, spindle speed, and tool changes. Combined with CAD/CAM, CNC enables rapid prototyping and mass customisation.
CNC（计算机数控）机器执行 G 代码指令，沿精确轨迹移动刀具。G 代码指令指定进给速率、主轴转速和换刀。结合 CAD/CAM，CNC 可实现快速原型制作和大规模定制。
Quality management terms include Lean manufacturing, which focuses on eliminating waste (muda). Just In Time (JIT) delivers materials only when needed, reducing inventory. Six Sigma is a data-driven approach to reduce defects to fewer than 3.4 per million opportunities. Total Quality Management (TQM) involves all employees in continuous improvement.
质量管理术语包括精益制造，专注于消除浪费（muda）。准时化生产 (JIT) 在需要时才配送物料，减少库存。六西格玛 是一种数据驱动方法，旨在将缺陷降低至每百万次机会不超过 3.4 个。全面质量管理 (TQM) 让所有员工参与持续改进。
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