目前並沒有全球統一的標準明確規定球墨鑄鐵的球化率必須達到80%以上才能被稱為球墨鑄鐵，但不同的國際標準和國家標準對球化率確實有相關規定或指引。例如：

1. 國際標準
ISO 1083 Spheroidal graphite cast irons —Classification（球墨鑄鐵國際標準）

ISO標準並未明確要求球化率的最低百分比，而是以球墨鑄鐵的機械性能（如抗拉強度、延伸率等）為主進行分類。

如果石墨球化程度過低，則機械性能可能無法達到要求。 ( 換句話說 抗拉力才是重點 請各位客戶別被誤導 )

7.2.2Test pieces machined from samples cut from a casting 

從鑄件上切取樣品加工的試驗件

If applicable, the manufacturer and the purchaser shall agree on:

如適用，製造商和購買方應就以下事項達成協議：

the location(s) on a casting where the sample(s) shall be taken;

切取樣品的鑄件位置

he mechanical properties that shall be measured;

要測量的機械性能；

the minimum values or allowable range of values, for these mechanical properties . 

這些機械性能的最低值或允許的範圍

以上要求都要買賣方同意 , 單方面的檢驗完全不符合法規要求 

7.2.4. Graphite structure  石墨結構

The graphite structure shall be mainly of form VI and V in accordance with ISO 945-1. 

A more precise definition may be agreed between the manufacturer and the purchaser. 

      --->  製造商與買方協議訂定更明確的定義  <----     

 This structure shall be confirmed either by metallographic examination or by non-destructive methods.

In case of dispute, the result of the metallographic examination shall prevail. 

此結構應通過金相檢驗或無損檢測方法進行確認。如有爭議，以金相檢驗結果為準。

Annex F     (informative)  （資料性內容）
Nodularity (or spheroidal graphite rate)     球化率（或球狀石墨比例）
The nodularity of spheroidal graphite cast iron is defined as the percentage of graphite particles that are spheroidal or nodular in shape (form V and VI of ISO 945-1). 

球墨鑄鐵的球化率定義為石墨顆粒中具有球狀或結節狀形態（ISO 945-1 的 V 型和 VI 型）所佔的百分比。

This percentage is generally determined at 100 x magnification on a polished, cut section of a sample. It may also be determined by image analysis, at higher magnification, or even, after prior calibration, by measuring the ultrasonic velocity across the material. 

此百分比通常在放大100倍的拋光樣品截面上測定。也可以通過影像分析在更高的放大倍率下測定，或者經過預先校準後，通過測量材料內的超聲波速度來確定。

The level of nodularity depends not only on the manufacturing process (charge material, residual magnesium content, inoculation mode, etc.) but also on the cooling modulus of the section in question. Moreover, some degeneration of the graphite in contact with the mould is occasionally observed. 

球化率的水平不僅取決於製造工藝（如爐料、殘餘鎂含量、鑄造方式等），還取決於相關截面的冷卻模數。此外，有時會觀察到石墨與模具接觸時的退化現象。

It is not possible to fix precisely, a critical level of nodularity with respect to the minimum characteristics appearing in this International standard, even for a specified cooling modulus, because the level varies not only with the measuring method used but also with the grade of cast iron in question (in particular its chemical composition), the pearlite content and, to some extent, the number of graphite particles per unit area.

即使針對特定的冷卻模數，也無法精確地確定在這個國際標準中出現的最小特徵的關鍵球化程度，因為球化程度不僅會隨著使用的測量方法而變化，還會隨著所討論的鑄鐵等級（特別是其化學成分）、波來鐵含量以及在一定程度上單位面積的石墨顆粒數量而變化。

備註: 由於諸多因素影響，國際標準中規定的最低標準與實際應用中所需的球化程度之間，存在著難以精確對應的關係。 即使在相同冷卻條件下，不同的鑄鐵材料、不同的測量方法，都會導致球化程度的結果有所差異。因此，不能簡單地認為達到標準中的最低要求就能滿足所有實際應用需求。

However, a level of nodularity of 80 % to 85 % or more generally ensures (more than enough for Rp0,2) the minimum tensile properties specified in this International Standard. Most of the 15 % to 20 % of graphite not in form VI and V is then in form IV and possibly in form III.

然而，通常來說，80%至85%或更高的球化程度（對於Rp0.2來說已經足夠）能夠確保達到本國際標準中規定的最低抗拉性能。 剩餘的15%至20%非VI型和V型石墨大部分以IV型存在，可能還有少量III型石墨。  這段規範最重要的一點是  球化率是要*確保* ENSURES  MINIMUM  TENSILE   抗拉力 抗拉力 抗拉力 

For castings subjected to severe loading, in particular under fatigue conditions, a higher nodularity (including requirements for a specific percentage of form VI and V graphite) may be required. Such a requirement should be evaluated by an experimental study, specific to the casting and the material grade. 

對於在嚴苛載荷下，尤其是在反覆載荷條件下工作的鑄件，單純滿足標準中的最低球化程度要求是不夠的。可能需要更高的球化程度以及對理想石墨形態（VI型和V型）的比例有更嚴格的要求。 這些要求不能一概而論，而需要針對具體的鑄件和材料等級，通過實驗研究來確定。 這段話強調了在特定應用環境下，根據實際需要制定更嚴格的性能要求的重要性。

2. 美國標準

ASTM A536 章節  Standard Specification for Ductile Iron Castings： (球墨鑄鐵規範)

1.1 This specification covers castings made of ductile iron also known as spheroidal or nodular iron, which is described as cast iron with the graphite substantially spheroidal in shape and essentially free of other forms of graphite, as defined in Terminology .

1.1本規範涵蓋由球墨鑄鐵製成的鑄件，也稱為球狀石墨鑄鐵或結節狀鑄鐵，其特徵是鑄鐵中的石墨主要呈球狀分佈，且基本不含其他形式的石墨，具體定義見術語部分。

4. Tensile Requirements  抗拉要求

Tensile strength, min, MPa     415 以上  包含 415

9. Chemical Requirements 化學要求 

It is the intent of this specification to subordinate chemical composition to mechanical properties; however, any chemical requirements may be specified by agreement between the manufacturer and the purchaser.

本規範旨在以機械性能為主，化學成分為輔；然而，任何化學成分的要求可由製造商與採購方協議決定。

ASTM 247-24  章節 :  Standard Test Method for Visual Evaluation of Graphite in Iron Castings ( 鑄鐵件中石墨的目視評估標準測試方法  )

 以下有兩大項重點

 1.2 The reference photomicrographs included in this test method are in no way to be construed as specifications. In an appropriate specification for a specific material where graphite microstructure is an important consideration, this test method may be used as a reference to concisely define the graphite microstructure required.

1.2 本測試方法中包含的參考顯微照片絕不應被解釋為規範。在適當的規範中，若對某特定材料而言石墨的顯微結構是一項重要考量，本測試方法可作為參考，用於簡明定義所需的石墨顯微結構。

10.  Nodularity   (球化率)

10.1 Nodularity (Figs. 6 and 7) is expressed by counting the nodular particles and reporting the results as a percentage of the total amount of graphite present in the microstructure. Ductile irons typically exhibit a nodularity between 80 to 100 %, gray irons a nodularity of 0 %, and compacted graphite irons a nodularity of 0 to 20 %. Nodularity should be assessed by evaluating more than one field of view. The final report should state the number of fields of view or area of the sample evaluated. The location of the measurement should be agreed upon between the manufacturer and purchaser.

球化率是通過計算球狀顆粒數量，並將結果以石墨微結構中石墨總量的百分比表示的。通常，球墨鑄鐵的球化率在 80% 至 100% 之間，灰口鑄鐵的球化率為 0%，而蠕墨鑄鐵的球化率則介於 0% 至 20% 之間。球化率的評估應基於多個視野的觀察。最終報告應說明評估過的視野數量或樣本的評估區域。測量位置應由製造商與購買者雙方協商一致後確定。

 11. Nodule count  ( 計算球化率 )

11.1 Nodule count is expressed as the number of graphite nodules/mm2 and is performed at a magnification of 100×. Generally, high nodule count indicates good metallurgical quality, but there is an optimum range of nodule count for each section size of casting, and nodule counts in excess of this range may result in a degradation of properties. Nodule count should be established between the manufacturer and the purchaser.

球數以每平方毫米的石墨球數量（graphite nodules/mm²）來表示，測量是在100倍顯微鏡放大倍率下進行的。一般而言，高球數表示良好的冶金品質，但對於鑄件的每種截面尺寸而言，球數都有一個最佳範圍。超出此範圍的球數可能會導致材料性能的劣化。計算球化率的標準應由製造商與購買者雙方協商確定。

12. Report of Graphite Microstructure  (石墨微結構報告)

12.3.2 A high-quality ductile iron could be designated I6. A slightly inferior ductile iron, with somewhat insufficient nodu-lizing alloy, might be 70 % I6, 30 % IV5.

12.3.2 高品質的球墨鑄鐵可標記為 I6。稍次的球墨鑄鐵，由於球化合金略有不足，可能由 70% 的 I(圓點顯微鏡圖示)6 和 30% 的 IV(蠕蟲顯微鏡圖示)5 組成。

3. 台灣標準 

CNS  2869  法規 採自願性實施 . 取樣是用試棒  

備註: 自願性實施基於 合約 規範 要在採購規範明定才有效力