6.6.1 Impellers shall be of the fully enclosed, semi-open or open type.
叶轮应该是封闭叶轮，半开叶轮或者开式叶轮
NOTE Enclosed (closed) impellers are less sensitive to axial position and, therefore, preferable for long shaft assemblies where axial displacement due to thermal expansion/contraction or to thrust can be substantial. Semi-open impellers can offer a higher efficiency, due to the elimination of disc friction from one shroud. The running clearances for semi-open impellers in vertical pumps can be adjusted from the coupling or top of the motor, thus possibly restoring efficiency and pump output without disassembly of pump parts. The open impeller is typically of an axial-flow propeller type designed for large capacities at low heads; the open impeller is also used for volute sump pumps with a separate discharge.
注：封闭式叶轮对轴向位置的敏感性较低，因此适用于因热膨胀/收缩或推力而产生较大轴向位移的长轴组件。半开式叶轮可以提供更高的效率，这是因为消除了一个端盖的圆盘摩擦。立式泵中半开式叶轮的运行间隙可从联轴器或电机顶部进行调整，从而有可能在不拆卸泵部件的情况下恢复效率和输出。开式叶轮通常为轴流式螺旋桨类型，用于低扬程下的大容量的场合；开式叶轮也可用于具有单独排放口的涡壳式污水泵。
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解释：石油化工行业，还是以半开式叶轮和闭式叶轮为主。
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6.6.2 Impellers shall be single-piece castings, forgings, or fabrications.
叶轮应为单件铸件、锻件或加工件。
NOTE Impellers made as forgings or fabrications have machined waterways, which can offer improved performance for
low-specific-speed designs.
注：锻件或加工件制成的叶轮具有机加工水道，可提高低比转速设计的泵的性能。
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解释：闭式叶轮，要么整体铸造，流道靠精铸或者简单加工就能满足效率要求。锻件则需要锻造后掏出流道，机加工的精度要远远大于铸造叶轮，但是掏出流道的过程十分困难。叶轮也可时两件焊的机构，就是流道和一端的端盖是通过机加工完成的，剩下的一个端盖通过焊接完成。
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6.6.3 Impellers shall be keyed to the shaft. Pinning of impellers to the shaft is not acceptable. With the purchaser's approval, collets may be used in vertically suspended pumps. Overhung impellers shall be secured to the shaft by a cap screw or cap nut that does not expose shaft threads. The securing device shall be threaded to tighten by liquid drag on the impeller during normal rotation, and a positive mechanical locking method (e.g. a staked and corrosion-resistant set-screw or a tongue-type washer) is required. Cap screws shall have fillets and a reduced-diameter shank to reduce stress concentrations.
叶轮必须用键固定在轴上。不允许将叶轮用销固定在轴上。经购买方批准，可在垂直悬吊泵中使用夹头。悬臂叶轮必须用不露出轴螺纹的盖形螺钉或盖形螺母固定在轴上。固定装置必须有螺纹，以便在正常旋转时通过叶轮上的液体阻力进行拧紧，并且必须采用可靠的机械锁定方法（例如，固定和耐腐蚀的固定螺钉或舌形垫圈）。盖帽螺钉应具有圆角和直径较小的柄，以减少应力集中。
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解释：夹头（collets）就是一个锥形的夹具，随着套上叶轮后，锥形会缩小，仅仅抱住轴或者collet driver（如下图）
带轮冒的叶轮图shaft by a cap screw，下图的6号件，叶轮锁帽锁紧方向应该和旋转方向相反，这样才能越转越紧，见下图。
tongue-type washer是一种有舌片的垫圈，通常用于防止螺母和其他紧固件的松动，后面有附图。
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6.6.4 All shaft keyways shall have fillet radii in accordance with ASME B17.1 or ISO 3117.
所有轴键槽的圆角半径必须符合 ASME B17.1 或 ISO 3117 标准。
6.6.5 Impellers shall have solid hubs. Impellers may have cored hubs if the core is completely filled with a suitable metal that has a melting point of not less than 1000 °F (540 °C).
叶轮应为实心轮毂。如果轮毂芯完全由熔点不低于 1000 °F（540 °C）的合适金属填充，则叶轮可使用有芯轮毂。
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解释：cored hubs是一种有空心芯的轮毂，cored hubs的优点是，它们可以减轻叶轮的重量，降低材料成本，降低铸造冷却时的变形。cored hubs的缺点是，它们需要用合适的金属填充空心芯，以防止空心芯的腐蚀、破裂或变形。同时如果是封闭的空心，且空心没有金属填充，则在拆装叶轮时需要对叶轮加热会导致空心内的残留液体膨胀，可能产生危险。
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NOTE The requirement to fill cored impeller hubs is intended to minimize the danger to personnel if and when impellers are removed by heating.
注：要求对空心轮毂进行填充，是为了在叶轮被加热拆卸时尽量减少对人员造成的危险。
6.6.6 For shafts that require sleeve gaskets to pass over threads, at least 0.06 in. (1.5 mm) radial clearance shall be provided between the threads and the internal diameter of the gasket, and the diameter transition shall be chamfered in accordance with 6.3.15.
对于需要轴套垫片穿过螺纹的轴，螺纹和垫片内径之间必须留有至少 0.06 英寸 （1.5 毫米）的径向间隙，过渡直径必须按照 6.3.15 倒角。
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解释：防止垫片或者螺纹损坏。
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6.6.7 The shaft-to-seal sleeve fit(s) shall be F7/h6 in accordance with ISO 286 (all parts).
密封处的轴套的配合应为 F7/h6，符合 ISO 286 标准（所有部件）。
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解释：F7/h6是一种间隙配合，轴和密封轴套之间还要增加密封圈的。
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6.6.8 Areas of shafts that can be damaged by set-screws shall be relieved to facilitate the removal of sleeves or other components.
轴上可能被固定螺钉损坏的部位应减轻处理，以便于拆卸轴套或其他部件。
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解释：怕拆轴套时，因为螺钉损坏了轴表面，无法拆除轴套。所谓relieved就是，是一种机械加工的方法，指的是在轴的某些部位减小直径，形成一个凹槽或一个锥形的表面
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6.6.9 Shafts shall be single-piece construction, machined, and finished throughout their length so that the total indicated runout (TIR) is not more than 0.001 in. (25 μm). Shafts constructed of multiple pieces assembled together，such as stub shaft extensions to drive lube oil pumps, shall require purchaser’s approval.
轴必须为单件结构，并在整个长度范围内进行机加工和精加工，使总指示跳动 (TIR) 不超过 0.001 英寸（25μm）。由多个部件组装在一起的轴，如用于驱动润滑油泵的短轴加长杆，必须获得买方的批准。
6.6.10 If noncontacting shaft vibration probes are furnished in accordance with 7.5.2.2, the shaft sensing areas (both radial vibration and axial position) for observation by radial vibration probes shall:
如果按照 7.5.2.2 配备了非接触式轴振动探头，则通过径向振动探头观测的轴传感区域（包括径向振动和轴向位置）必须是
a) be concentric with the bearing journals;
与轴承轴颈同心；
b) be free from stencil and scribe marks or any other surface discontinuity, such as an oil hole or a keyway, for a minimum distance of one probe tip diameter on each side of the probe;
远离钢印和刻划痕迹或任何不连续表面，如油孔或键槽，且最小距离为一个探针头直径的距离
c) not be metallized, sleeved, or plated on rotors made of materials that exhibit consistent electrical properties;
不得在用电子特性一致化的金属轴上，进行金属化、带轴套或电镀；
d) have a final surface finish of 32 μin. (0.8 μm) Ra or smoother, preferably obtained by honing or burnishing;
最终完成的表面Ra 32 μin. (0.8 μm) 或更光滑，推荐通过珩磨或抛光获得这个光滑度
e) be properly demagnetized to the levels specified in API 670, or otherwise treated so that the combined total electrical and mechanical runout does not exceed the following:
经过适当消磁，达到 API 670 规定的水平，或经过其他处理，使电气和机械跳动的总和不超过以下值：
- for areas observed by radial vibration probes, 25 % of the allowed peak-to-peak vibration amplitude or
0.25 mil (6 μm), whichever is greater;
对于径向振动探头探测的区域，允许振动峰-峰振幅的 25 % 或0.25 mil (6 μm)，以较大者为准；
- for areas to be observed by axial position probes, 0.5 mil (13 μm).
对于轴向位置探头要探测的区域，0.5 mil（13 微米）。
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解释：以上的整体要求，就是对测振区域的要求，包括同心要求，表面光洁和表面粗糙度要求，以及跳动要求。
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解释：如下测振区域的TIR跳动要求，远高于轴的其他部位，（其他部位的最大TIR为25微米）
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6.6.11 If the shaft is made of material that exhibits inconsistent electrical properties, the shaft-sensing areas may be produced by shrink-fitting sleeves or target rings on the shaft. Target rings shall be finished in accordance with 6.6.10 and shall be identified in the technical documentation. Materials known to exhibit inconsistent electrical properties are high-chromium alloys such as 17-4 PH, duplex stainless steel, and many austenitic stainless steels.
如果轴是由电子性能不一致的材料制成，则轴感应区可通过轴上的过盈配合轴套或靶环制作。靶环的加工应符合 6.6.10 的规定，并应在技术文件中注明。已知电子性能不一致的材料有高铬合金（如 17-4 PH）、双相不锈钢和许多奥氏体不锈钢
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解释：也就是说，17-4ph，双相钢和奥氏体不锈钢的测振动区域必须带有轴套（因为他们表现出电子性能不一致）。但是根据实际情况，以上材料做的轴不会在测振区域再增加轴套。
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6.6.12 If provisions for mounting noncontacting shaft vibration probes are specified (7.5.2.2), the shaft shall be prepared in accordance with the requirements of 6.6.10 and API 670.
如果指定了安装非接触式轴振动探头的规定（7.5.2.2），则必须按照 6.6.10 和 API 670 的要求准备轴。
6.6.13 If noncontacting shaft vibration probes are furnished, accurate records of electrical and mechanical runout for the full 360° at each probe location shall be included in the mechanical test report. Electrical and mechanical runout records shall be phase referenced to a permanent location on the shaft such as a key slot.
如果提供的是非接触式轴振动探头，机械测试报告中应包括每个探头位置 360° 全程的电气和机械跳动的准确记录。电气和机械跳动记录应与轴上的永久位置（如键槽）相对照。