Quick Answer: If a Japanese buyer asks for JIS ferrosilicon, the product standard is JIS G 2302, which sets the grades, composition and size. JIS G 1312-1 is not a second specification: it only tells the laboratory how to measure silicon. For about 75% silicon, the grade to check is FSi 2, listed at 75–80% Si in the main text. A quote for "FeSi75" does not guarantee that. Ask the supplier to confirm FSi 2 in writing, then check every batch report against your purchase order.
Table of Contents
- What Does JIS G 2302 Specify for Ferrosilicon?
- JIS G 2302 Ferrosilicon Grades and Composition
- Is FeSi 75 Equivalent to JIS FSi 2?
- JIS G 1312-1: How Silicon Content Is Determined
- How to Specify JIS Ferrosilicon in a Purchase Order
- How to Check a JIS Ferrosilicon Batch COA
- JIS Ferrosilicon Specification FAQs
- Is the 1998 edition of JIS G 2302 still valid?
- Does a silicon result by JIS G 1312-1 prove the whole batch conforms?
- What is the difference between a JIS conformity statement and the JIS Mark?
- Can ordinary FeSi75 be supplied to JIS FSi 2?
- What should I send a supplier when I need JIS ferrosilicon?
If you received an inquiry or a technical annex from a Japanese customer that cites JIS ferrosilicon, this article shows you which standard answers which question, and how to turn it into a purchase order and a batch check. It does not reproduce the standard. Always work from the current text you have bought or been given.
What Does JIS G 2302 Specify for Ferrosilicon?
JIS G 2302 covers ferrosilicon as a product. Japan's standards association lists it as JIS G 2302:1998, and its listing shows the standard as current, with a confirmation date of 20 October 2023. The 2023 date is when the standard was reconfirmed. The number and the 1998 edition did not change, so do not describe it as withdrawn or as a 2023 edition.
The standard sets grades, chemical composition and size requirements, and it deals with sampling, inspection and marking. Some requirements sit in the main text and others in normative annexes. In a purchase order, state which of them you are applying, because a supplier who is working to the main text only will not be covering an annex you assumed.
JIS G 2302 Ferrosilicon Grades and Composition
The main text of JIS G 2302 includes the grades FSi 1, FSi 2, FSi 3 and FSi 6. The Japan Ferroalloy Association handbook lists the main-text silicon range of FSi 2 as 75–80% by mass and of FSi 3 as 40–45% by mass. Read the other grades, the other elements and the size classes from the standard itself.
| What to check | Where it comes from | Why it matters |
|---|---|---|
| Grade | Standard grade name, for example FSi 2 | The grade fixes the silicon range |
| Basic composition | Grade table in the standard | Limits that apply to every delivery of that grade |
| Specified composition | Your order, where the standard allows it | Extra limits are only binding if you write them in |
| Customer limits | Contract or technical annex | Your own limits on aluminium, carbon or other elements |
| Size | Standard size requirement or contract | Size and tolerance are accepted separately from chemistry |
Is FeSi 75 Equivalent to JIS FSi 2?
No, not by name alone. Suppose a buyer asks for main-text FSi 2, and the supplier quotes "FeSi75, Si 75% min." That quote promises a floor of 75% silicon. FSi 2 is a range of 75–80%, so the quote says nothing about the upper limit. It also says nothing about the other requirements in the standard.
Even when a batch result falls inside 75–80%, that is one item in the check, not the whole acceptance. The supplier's guaranteed values must match the standard and your contract before you treat the product as FSi 2. For our general FeSi75 supply, see our ferrosilicon products and ask us to confirm any JIS item you need.
JIS G 1312-1: How Silicon Content Is Determined
JIS G 1312-1:2011 is a test method. It tells a laboratory how to determine silicon in ferrosilicon, and it belongs on a report as the basis for the silicon result. It does not give the grade limits, and it cannot show that a whole delivery conforms.
It is Part 1 and covers silicon only. For other elements, check which standard part or method the contract names. When a COA lists silicon with a method, confirm that the method is the one your contract expects.
How to Specify JIS Ferrosilicon in a Purchase Order
Treat the PO as the place where the standard becomes binding. The following items cover most disputes:
| PO item | What to write |
|---|---|
| Standard and edition | JIS G 2302:1998, as confirmed |
| Main text or annex | Which part of the standard applies |
| Grade | For example FSi 2, not only "FeSi75" |
| Extra element limits | Any limit beyond the standard, stated as a number |
| Size and tolerance | The size class and allowed deviation |
| Sampling and test basis | Who samples, and which test methods apply |
| Batch documents | Batch number and the report that must travel with the lot |
How to Check a JIS Ferrosilicon Batch COA
Check the report in three passes. First, compare each result with the PO limit, not only with the supplier's own range. Second, confirm the test basis, such as JIS G 1312-1 for silicon, matches what the PO names. Third, match the batch number on the report to the batch marked on the delivered material, so the result belongs to the lot you received.
A report that passes all three tells you the reported sample met the contract. It does not replace the inspection and sampling rules your contract sets for the whole delivery. Our COA guide for FeSi75 explains the report fields in detail.
Send us your standard number, grade, size and documents you require, and we will tell you which items we can confirm in writing before you place the order. We do not describe our material as JIS-certified unless we can show the evidence.
Send Your JIS Ferrosilicon Specification
JIS Ferrosilicon Specification FAQs
Is the 1998 edition of JIS G 2302 still valid?
Japan's standards association lists JIS G 2302:1998 as current, with a confirmation date of 20 October 2023. Check the listing again before you cite it, because status can change.
Does a silicon result by JIS G 1312-1 prove the whole batch conforms?
No. The method shows how silicon was determined for the tested sample. Conformity depends on the grade limits, the other requirements and the sampling and inspection rules in your contract.
What is the difference between a JIS conformity statement and the JIS Mark?
A supplier can state that a product meets a standard. The JIS Mark is a certification issued through a registered certification body. Do not treat one as the other, and ask for the certificate if you require the mark.
Can ordinary FeSi75 be supplied to JIS FSi 2?
Only if the supplier guarantees values that meet FSi 2 and the other items in your contract. The name FeSi75 alone is not enough, and Si 75% min. does not cover the upper limit.
What should I send a supplier when I need JIS ferrosilicon?
Send the standard number and edition, grade, any added element limits, size and tolerance, test basis and the batch documents you require.
