Improve the shower door glass
Self-explosion of tempered glass
The automatic explosion of tempered glass without direct mechanical external force is called self-explosion of tempered glass, and self-explosion is one of the inherent characteristics of tempered glass.
A. There are many reasons for spontaneous explosion. Simply summarize the following:
①The influence of glass defects
A. There are stones and impurities in the glass: The impurities in the glass are weak points of tempered glass and stress concentration points. Especially if the stone is in the tensile stress zone of the tempered glass, it is an important factor that causes the explosion.
Stones exist in the glass and have a different expansion coefficient from the glass body. After glass tempering, the stress concentration in the crack area around the stone increases exponentially. When the coefficient of expansion of the stone is smaller than that of glass, the tangential stress around the stone is in tension. The crack propagation that accompanies the stone is easy to occur.
B. The glass contains nickel sulfide crystals.
Nickel sulfide inclusions generally exist as small crystalline spheres with a diameter of 0.1-2 mm. The appearance is metallic. These miscellaneous inclusions are NI3S2, NI7S6 and NI-XS, where X=0—0.07. Only the NI1-XS phase is the main cause of spontaneous explosion of tempered glass.
The theoretical NIS is known to be 379. At C, there is a phase transition process, from the high temperature state a-NIS hexagonal crystal system to the low temperature state B-NI trigonal crystal system, accompanied by 2.38% volume expansion. This structure is preserved at room temperature. If the glass is heated in the future, a-B state transition may occur quickly. If these impurities are inside the tempered glass under tensile stress, the volume expansion will cause spontaneous explosion. If a-NIS exists at room temperature, it will slowly change to the B state after several years and months. The slow increase in volume during this phase change does not necessarily cause internal rupture.
C. The glass surface has defects such as scratches, blasting, deep blasting due to improper processing or operation, which may cause stress concentration or cause the tempered glass to explode.
②Uneven stress distribution and offset
When the glass is heated or cooled, the temperature gradient along the thickness of the glass is uneven and asymmetric. Toughened products have a tendency to explode, and some produce "wind explosion" when they are chilled. If the tensile stress zone shifts to a certain side of the product or shifts to the surface, the tempered glass will explode.
③The influence of tempering degree
③The influence of the degree of toughening. Experiments have shown that when the degree of toughening is increased to level 1/cm, the number of self-detonations reaches 20-25%. It can be seen that the greater the stress, the higher the degree of toughening, and the greater the amount of self-detonation.
B:Will the tempered glass used in the shower room explode?
Qualified shower rooms use toughened glass, which is based on safety considerations. If ordinary glass is used to make the shower room, once the glass is damaged, the glass fragments will be large-scale and large-volume fragments, which will cause great harm to the human body, cutting skin, muscles, blood vessels, etc. It is very important to choose qualified tempered glass. The above-mentioned hazards can be completely avoided regardless of whether the glass is artificially broken or exploded. Although full tempering will increase the rate of self-detonation, the size of the fragments after bursting can be completely controlled within the scope of the national standard. If semi-tempered, the fragments will cause serious harm to the human body. At the same time, the shower room glass needs to be clamped by hardware. The semi-tempered glass is not only unable to reduce the spontaneous explosion rate due to the obvious decrease in firmness, but it will increase the possibility of spontaneous explosion under the tightening action of the hardware.
C. New national standards for shower rooms are released
In order to reduce the threat of this kind of shower room to people’s life safety, the state issued a new shower room recommendation standard on June 7, 2018, and formally implemented it on July 1, 2019. The standard stipulates that the shower room glass must be made of film or Only by the way of laminating can it flow out of the market. At present, the standard is in a recommended state, and it has not yet been compulsory for enterprises to implement it. It also gives enterprises a time for transformation and adaptation. It is believed that this standard will be converted into a mandatory standard in the near future, which will provide consumers with a safe and secure shower space.
In addition to filming and laminating treatment can reduce the harm of tempered glass self-explosion to people by the shower door company, you can also choose a shower room made of acrylic, which has absolutely no risk of self-explosion. It is understood that the price of the shower room is not much different from the film shower room. It is predicted that the shower room made of acrylic may occupy a dominant position in the cheap shower enclosures market in the future.