Tungsten carbide

Auto flammability

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

relative self-ignition temperature (solids)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-06-30 to 2010-08-12

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

GLP study, conducted according to N.4 in Part III, subsection 33.3.1.6 of the United Nations Recommendations on the Transport of Dangerous Goods-Manual of Tests and Criteria 4th Revised Edition. Detailed sample characterization was included.

Justification for type of information:

1. HYPOTHESIS FOR THE CATEGORY APPROACH: The hypothesis is that properties are likely to be similar or follow a similar pattern because of the presence of a common metal ion, in this case tungstate.
2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES):
Source: Tungsten Carbide
Target: RM W2C + WC
3. CATEGORY APPROACH JUSTIFICATION: See Annex 1 in CSR
4. DATA MATRIX: See Annex 1 in CSR

Qualifier:

according to guideline

Guideline:

other: to N.4 in Part III, subsection 33.3.1.6 of the United Nations Recommendations on the Transport of Dangerous Goods-Manual of Tests and Criteria 4th Revised Edition.

GLP compliance:

yes

Key result

Relative self-ignition temperature:

> 140 °C

Remarks on result:

other: 100 mm cube at 140 degrees C

Remarks:

at atm. press. of 1013.0 hPa

100 mm cube at 140 °C = no ignition

None of the test substance samples ignited during the test. Furthermore, the sample temperature for all three test substance samples never exceeded the oven temperature by 60 °C. Therefore, it can be concluded that tungsten carbide is not a self-heating substance at the particle sizes tested.

Conclusions:

None of the test substance samples ignited during the test. Furthermore, the sample temperature for all three test substance samples never exceeded the oven temperature by 60 °C. Therefore, it can be concluded that tungsten carbide is not a self-heating substance at the particle sizes tested.

Reference 2

Endpoint:

relative self-ignition temperature (solids)

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Reliability assigned by secondary source. Only secondary source reviewed.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

EU Method A.16 (Relative Self-Ignition Temperature for Solids)

GLP compliance:

not specified

Relative self-ignition temperature:

> 300 °C

Remarks on result:

other:

Remarks:

at atm. press. of 1013.0 hPa

The autoignition temperature depends on the type of powder. For a commercially available powder, the observed auto ignition temperature was > 300 °C. Pressure was not reported, assumed to be conducted under standard conditions.

Description of key information

Three samples of tungsten carbide were tested in a standard test for self-heating. None of the test substance samples ignited during the test.  Furthermore, the sample temperature for all three test substance samples never exceeded the oven temperature by 60°C. Therefore, it can be concluded that tungsten carbide is not a self-heating substance at the particle sizes tested. Testing was conducted down to a particle size of 0.53 µm (FSSS size) (nominally 0.47 µm).