"Our Steel Is Not Like Banana" - Engr. Morales

During a meeting with the Department of Trade and Industry (DTI) last May 11, 2018, Senator Nikki Coseteng and Engineer Emilio Morales presented a series of questions directed towards the steel manufacturers regarding the use of Quenched Tempered (QT/TMT) steel. 

After they presented their queries, Wellington Tong, chair of the PAGASA Steel, stated that it would be difficult to answer all the presenters’ questions. Tong then proceeded to explain the lengthy process of manufacturing Quenched Tempered (QT/TMT) steel, at the same time clearing up a few misunderstandings and answering some questions. 

“Our steel is not like a banana where you can peel off the skin. It is a composite material but it is one piece. You can’t peel it,” he said after claims were made that quenching allows the outer core to have a tough, brittle exterior. “Although the cross section shows different colors, it is still one piece of steel! It's not like a banana where you peel a skin, not like an onion where you can peel off a layer.”

However, it was explicitly clear in the presentations made by Engineer Morales, that the outer skin of the QT/TMT rebar is made up of a thin layer of Martensite, which although very strong, is also prattle and less ductile. Should this skin be damaged as in normal construction operations, the strength of the rebar degrades and premature failure can occur during seismic loading.

Tong added that quenched steel provided for more ductile and stronger steel without the use of vanadium which based on the MIRDC report commissioned by PISI is not totally correct. 

In fact, he suggested that QT/TMT steel comparable to Micro Alloy (MA) steel, which is what has been previously used, as MA rebars also has restrictions when it comes to welding and bending.

However, both Senator Nikki Coseteng and Engineer Morales were still left unsatisfied by his lengthy and technical presentation which only explained the manufacturing process without directly addressing the critical issues and the safety of the Rebar when used in Seismic Zone 4.: Why were the public and engineering community uninformed of this change?

It was confirmed in the DTI forum, that many engineers and contractors were unaware that they are using QT/TMT. Is it not their right and the consumers’ right to know exactly what kind of steel they are using in their structures? 

Since the root of the issue first arose, the steel manufacturer’s position have been put on hold. “Further testing is needed”, but this position has been the standard line for over 10 years now, which the former solon believed to be their regular dilatory tactic. In the meantime, QT/TMT bars are still being sold and used by the blindsided public.

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